diff --git a/examples/Console/Examples.Console.csproj b/examples/Console/Examples.Console.csproj
index 26662ab86ea..68f89702451 100644
--- a/examples/Console/Examples.Console.csproj
+++ b/examples/Console/Examples.Console.csproj
@@ -4,6 +4,7 @@
     <OutputType>Exe</OutputType>
     <TargetFramework>netcoreapp3.1</TargetFramework>
     <IsPackable>false</IsPackable>
+    <NoWarn>$(NoWarn),CS0618</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/OpenTelemetry.Api/CHANGELOG.md b/src/OpenTelemetry.Api/CHANGELOG.md
index 4a489ec7fbd..011b1ab7231 100644
--- a/src/OpenTelemetry.Api/CHANGELOG.md
+++ b/src/OpenTelemetry.Api/CHANGELOG.md
@@ -8,6 +8,12 @@
   extension) will now be set as the `Unset`, `Error`, or `Ok` string
   representation instead of the `0`, `1`, or `2` integer representation.
   ([#1579](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1579))
+* Metrics API/SDK support is in an experimental state and is not recommended for
+  production use. All metric APIs have been marked with the `Obsolete`
+  attribute. See
+  [#1501](https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501)
+  for more information.
+  ([#1611](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1611))
 
 ## 1.0.0-rc1.1
 
diff --git a/src/OpenTelemetry.Api/Metrics/BlankLabelSet.cs b/src/OpenTelemetry.Api/Metrics/BlankLabelSet.cs
index 2cdc7afe59b..70f9482cdd8 100644
--- a/src/OpenTelemetry.Api/Metrics/BlankLabelSet.cs
+++ b/src/OpenTelemetry.Api/Metrics/BlankLabelSet.cs
@@ -14,11 +14,14 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// Blank or No-op labelset.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class BlankLabelSet : LabelSet
     {
     }
diff --git a/src/OpenTelemetry.Api/Metrics/BoundCounterMetric.cs b/src/OpenTelemetry.Api/Metrics/BoundCounterMetric.cs
index 878f70797a6..5c62de07e91 100644
--- a/src/OpenTelemetry.Api/Metrics/BoundCounterMetric.cs
+++ b/src/OpenTelemetry.Api/Metrics/BoundCounterMetric.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using OpenTelemetry.Trace;
 
 namespace OpenTelemetry.Metrics
@@ -22,6 +23,7 @@ namespace OpenTelemetry.Metrics
     /// Bound counter metric with the defined <see cref="LabelSet"/>.
     /// </summary>
     /// <typeparam name="T">The type of counter. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class BoundCounterMetric<T>
         where T : struct
     {
diff --git a/src/OpenTelemetry.Api/Metrics/BoundMeasureMetric.cs b/src/OpenTelemetry.Api/Metrics/BoundMeasureMetric.cs
index 8ab3768f26b..69163a56267 100644
--- a/src/OpenTelemetry.Api/Metrics/BoundMeasureMetric.cs
+++ b/src/OpenTelemetry.Api/Metrics/BoundMeasureMetric.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using OpenTelemetry.Trace;
 
 namespace OpenTelemetry.Metrics
@@ -22,6 +23,7 @@ namespace OpenTelemetry.Metrics
     /// Bound measure metric with the defined <see cref="LabelSet"/>.
     /// </summary>
     /// <typeparam name="T">The type of Measure. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class BoundMeasureMetric<T>
         where T : struct
     {
diff --git a/src/OpenTelemetry.Api/Metrics/CounterMetric.cs b/src/OpenTelemetry.Api/Metrics/CounterMetric.cs
index 06f169021f6..46ce9a703c3 100644
--- a/src/OpenTelemetry.Api/Metrics/CounterMetric.cs
+++ b/src/OpenTelemetry.Api/Metrics/CounterMetric.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 using OpenTelemetry.Trace;
 
@@ -23,6 +24,7 @@ namespace OpenTelemetry.Metrics
     /// Counter instrument.
     /// </summary>
     /// <typeparam name="T">The type of counter. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class CounterMetric<T>
         where T : struct
     {
diff --git a/src/OpenTelemetry.Api/Metrics/DoubleObserverMetric.cs b/src/OpenTelemetry.Api/Metrics/DoubleObserverMetric.cs
index 1166b1addec..bb75b9eeded 100644
--- a/src/OpenTelemetry.Api/Metrics/DoubleObserverMetric.cs
+++ b/src/OpenTelemetry.Api/Metrics/DoubleObserverMetric.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 
 namespace OpenTelemetry.Metrics
@@ -21,6 +22,7 @@ namespace OpenTelemetry.Metrics
     /// <summary>
     /// Observer instrument for Double values.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class DoubleObserverMetric
     {
         /// <summary>
diff --git a/src/OpenTelemetry.Api/Metrics/DoubleObserverMetricHandle.cs b/src/OpenTelemetry.Api/Metrics/DoubleObserverMetricHandle.cs
index 835d44f2176..ec214d4d646 100644
--- a/src/OpenTelemetry.Api/Metrics/DoubleObserverMetricHandle.cs
+++ b/src/OpenTelemetry.Api/Metrics/DoubleObserverMetricHandle.cs
@@ -14,11 +14,14 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// Handle to the metrics observer with the defined <see cref="LabelSet"/>.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class DoubleObserverMetricHandle
     {
         /// <summary>
diff --git a/src/OpenTelemetry.Api/Metrics/Int64ObserverMetric.cs b/src/OpenTelemetry.Api/Metrics/Int64ObserverMetric.cs
index 4a437a5c01c..6f6c00f5d74 100644
--- a/src/OpenTelemetry.Api/Metrics/Int64ObserverMetric.cs
+++ b/src/OpenTelemetry.Api/Metrics/Int64ObserverMetric.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 
 namespace OpenTelemetry.Metrics
@@ -21,6 +22,7 @@ namespace OpenTelemetry.Metrics
     /// <summary>
     /// Observer instrument for Int64 values.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class Int64ObserverMetric
     {
         /// <summary>
diff --git a/src/OpenTelemetry.Api/Metrics/Int64ObserverMetricHandle.cs b/src/OpenTelemetry.Api/Metrics/Int64ObserverMetricHandle.cs
index b85a4ed3882..40e6ccb60b1 100644
--- a/src/OpenTelemetry.Api/Metrics/Int64ObserverMetricHandle.cs
+++ b/src/OpenTelemetry.Api/Metrics/Int64ObserverMetricHandle.cs
@@ -14,11 +14,14 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// Handle to the metrics observer with the defined <see cref="LabelSet"/>.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class Int64ObserverMetricHandle
     {
         /// <summary>
diff --git a/src/OpenTelemetry.Api/Metrics/LabelSet.cs b/src/OpenTelemetry.Api/Metrics/LabelSet.cs
index 9c71f944e5b..ea785a905f8 100644
--- a/src/OpenTelemetry.Api/Metrics/LabelSet.cs
+++ b/src/OpenTelemetry.Api/Metrics/LabelSet.cs
@@ -13,6 +13,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 // </copyright>
+
+using System;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -21,6 +23,7 @@ namespace OpenTelemetry.Metrics
     /// <summary>
     /// Normalized name value pairs of metric labels.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class LabelSet
     {
         /// <summary>
diff --git a/src/OpenTelemetry.Api/Metrics/MeasureMetric.cs b/src/OpenTelemetry.Api/Metrics/MeasureMetric.cs
index 173b21f3191..a00245ac90f 100644
--- a/src/OpenTelemetry.Api/Metrics/MeasureMetric.cs
+++ b/src/OpenTelemetry.Api/Metrics/MeasureMetric.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 using OpenTelemetry.Trace;
 
@@ -23,6 +24,7 @@ namespace OpenTelemetry.Metrics
     /// Measure instrument.
     /// </summary>
     /// <typeparam name="T">The type of measure. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class MeasureMetric<T>
         where T : struct
     {
diff --git a/src/OpenTelemetry.Api/Metrics/Meter.cs b/src/OpenTelemetry.Api/Metrics/Meter.cs
index 70bf0f97b01..9bac322408a 100644
--- a/src/OpenTelemetry.Api/Metrics/Meter.cs
+++ b/src/OpenTelemetry.Api/Metrics/Meter.cs
@@ -22,6 +22,7 @@ namespace OpenTelemetry.Metrics
     /// <summary>
     /// Main interface to obtain metric instruments.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class Meter
     {
         /// <summary>
diff --git a/src/OpenTelemetry.Api/Metrics/MeterFactoryBase.cs b/src/OpenTelemetry.Api/Metrics/MeterFactoryBase.cs
index 963cbb6f106..2967b747c90 100644
--- a/src/OpenTelemetry.Api/Metrics/MeterFactoryBase.cs
+++ b/src/OpenTelemetry.Api/Metrics/MeterFactoryBase.cs
@@ -22,6 +22,7 @@ namespace OpenTelemetry.Metrics
     /// Libraries should use this class as follows to obtain Meter instance.
     /// MeterFactoryBase.Default.GetMeter("libraryname", "version").
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class MeterFactoryBase
     {
         private static ProxyMeter proxyMeter = new ProxyMeter();
diff --git a/src/OpenTelemetry.Api/Metrics/MeterProvider.cs b/src/OpenTelemetry.Api/Metrics/MeterProvider.cs
index 6b574aef1a1..402f35572b2 100644
--- a/src/OpenTelemetry.Api/Metrics/MeterProvider.cs
+++ b/src/OpenTelemetry.Api/Metrics/MeterProvider.cs
@@ -21,6 +21,7 @@ namespace OpenTelemetry.Metrics
     /// <summary>
     /// MeterProvider is the entry point of the OpenTelemetry Metrics API. It provides access to Meters.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class MeterProvider : BaseProvider
     {
         private static ProxyMeter proxyMeter = new ProxyMeter();
diff --git a/src/OpenTelemetry.Api/Metrics/NoopBoundCounterMetric.cs b/src/OpenTelemetry.Api/Metrics/NoopBoundCounterMetric.cs
index acda009c1d7..fb93e223d57 100644
--- a/src/OpenTelemetry.Api/Metrics/NoopBoundCounterMetric.cs
+++ b/src/OpenTelemetry.Api/Metrics/NoopBoundCounterMetric.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using OpenTelemetry.Trace;
 
 namespace OpenTelemetry.Metrics
@@ -22,6 +23,7 @@ namespace OpenTelemetry.Metrics
     /// No-Op bound counter metric.
     /// </summary>
     /// <typeparam name="T">The type of counter. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopBoundCounterMetric<T> : BoundCounterMetric<T>
         where T : struct
     {
diff --git a/src/OpenTelemetry.Api/Metrics/NoopBoundMeasureMetric.cs b/src/OpenTelemetry.Api/Metrics/NoopBoundMeasureMetric.cs
index bb8d928e4db..ef73f02ec84 100644
--- a/src/OpenTelemetry.Api/Metrics/NoopBoundMeasureMetric.cs
+++ b/src/OpenTelemetry.Api/Metrics/NoopBoundMeasureMetric.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using OpenTelemetry.Trace;
 
 namespace OpenTelemetry.Metrics
@@ -22,6 +23,7 @@ namespace OpenTelemetry.Metrics
     /// No op measure handle.
     /// </summary>
     /// <typeparam name="T">The type of Measure. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopBoundMeasureMetric<T> : BoundMeasureMetric<T>
         where T : struct
     {
diff --git a/src/OpenTelemetry.Api/Metrics/NoopCounterMetric.cs b/src/OpenTelemetry.Api/Metrics/NoopCounterMetric.cs
index 70d4bd4849a..b1c028d9f78 100644
--- a/src/OpenTelemetry.Api/Metrics/NoopCounterMetric.cs
+++ b/src/OpenTelemetry.Api/Metrics/NoopCounterMetric.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 using OpenTelemetry.Trace;
 
@@ -23,6 +24,7 @@ namespace OpenTelemetry.Metrics
     /// A no-op counter instrument.
     /// </summary>
     /// <typeparam name="T">The type of counter. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopCounterMetric<T> : CounterMetric<T>
         where T : struct
     {
diff --git a/src/OpenTelemetry.Api/Metrics/NoopDoubleObserverMetric.cs b/src/OpenTelemetry.Api/Metrics/NoopDoubleObserverMetric.cs
index 5c0246dd4e3..c77b89b1443 100644
--- a/src/OpenTelemetry.Api/Metrics/NoopDoubleObserverMetric.cs
+++ b/src/OpenTelemetry.Api/Metrics/NoopDoubleObserverMetric.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 
 namespace OpenTelemetry.Metrics
@@ -21,6 +22,7 @@ namespace OpenTelemetry.Metrics
     /// <summary>
     /// A no-op observer instrument.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopDoubleObserverMetric : DoubleObserverMetric
     {
         /// <summary>
diff --git a/src/OpenTelemetry.Api/Metrics/NoopDoubleObserverMetricHandle.cs b/src/OpenTelemetry.Api/Metrics/NoopDoubleObserverMetricHandle.cs
index 6dfbaa20c76..e049d5e87f6 100644
--- a/src/OpenTelemetry.Api/Metrics/NoopDoubleObserverMetricHandle.cs
+++ b/src/OpenTelemetry.Api/Metrics/NoopDoubleObserverMetricHandle.cs
@@ -14,11 +14,14 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// No-Op observer handle.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopDoubleObserverMetricHandle : DoubleObserverMetricHandle
     {
         /// <summary>
diff --git a/src/OpenTelemetry.Api/Metrics/NoopInt64ObserverMetric.cs b/src/OpenTelemetry.Api/Metrics/NoopInt64ObserverMetric.cs
index 10a4a12cb3f..771ce2c36c3 100644
--- a/src/OpenTelemetry.Api/Metrics/NoopInt64ObserverMetric.cs
+++ b/src/OpenTelemetry.Api/Metrics/NoopInt64ObserverMetric.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 
 namespace OpenTelemetry.Metrics
@@ -21,6 +22,7 @@ namespace OpenTelemetry.Metrics
     /// <summary>
     /// A no-op observer instrument.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopInt64ObserverMetric : Int64ObserverMetric
     {
         /// <summary>
diff --git a/src/OpenTelemetry.Api/Metrics/NoopInt64ObserverMetricHandle.cs b/src/OpenTelemetry.Api/Metrics/NoopInt64ObserverMetricHandle.cs
index afe16a24ab9..db779d45262 100644
--- a/src/OpenTelemetry.Api/Metrics/NoopInt64ObserverMetricHandle.cs
+++ b/src/OpenTelemetry.Api/Metrics/NoopInt64ObserverMetricHandle.cs
@@ -14,11 +14,14 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// No-Op observer handle.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopInt64ObserverMetricHandle : Int64ObserverMetricHandle
     {
         /// <summary>
diff --git a/src/OpenTelemetry.Api/Metrics/NoopMeasureMetric.cs b/src/OpenTelemetry.Api/Metrics/NoopMeasureMetric.cs
index e935a01e08f..9cd6f2deb6d 100644
--- a/src/OpenTelemetry.Api/Metrics/NoopMeasureMetric.cs
+++ b/src/OpenTelemetry.Api/Metrics/NoopMeasureMetric.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 
 namespace OpenTelemetry.Metrics
@@ -22,6 +23,7 @@ namespace OpenTelemetry.Metrics
     /// No op measure instrument.
     /// </summary>
     /// <typeparam name="T">The type of counter. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopMeasureMetric<T> : MeasureMetric<T>
         where T : struct
     {
diff --git a/src/OpenTelemetry.Api/OpenTelemetry.Api.csproj b/src/OpenTelemetry.Api/OpenTelemetry.Api.csproj
index dfb0a8b517e..96c5b788b3e 100644
--- a/src/OpenTelemetry.Api/OpenTelemetry.Api.csproj
+++ b/src/OpenTelemetry.Api/OpenTelemetry.Api.csproj
@@ -3,6 +3,8 @@
     <TargetFrameworks>net452;netstandard2.0</TargetFrameworks>
     <Description>OpenTelemetry .NET API</Description>
     <RootNamespace>OpenTelemetry</RootNamespace>
+
+    <NoWarn>$(NoWarn),CS0618</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/OpenTelemetry.Exporter.Prometheus/OpenTelemetry.Exporter.Prometheus.csproj b/src/OpenTelemetry.Exporter.Prometheus/OpenTelemetry.Exporter.Prometheus.csproj
index 3594e71662f..6f95eae17a9 100644
--- a/src/OpenTelemetry.Exporter.Prometheus/OpenTelemetry.Exporter.Prometheus.csproj
+++ b/src/OpenTelemetry.Exporter.Prometheus/OpenTelemetry.Exporter.Prometheus.csproj
@@ -3,6 +3,7 @@
     <TargetFrameworks>net452;net46;netstandard2.0</TargetFrameworks>
     <Description>Prometheus exporter for OpenTelemetry .NET</Description>
     <PackageTags>$(PackageTags);Prometheus</PackageTags>
+    <NoWarn>$(NoWarn),CS0618</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/OpenTelemetry/CHANGELOG.md b/src/OpenTelemetry/CHANGELOG.md
index fa8db9e703e..5bc3778c4a9 100644
--- a/src/OpenTelemetry/CHANGELOG.md
+++ b/src/OpenTelemetry/CHANGELOG.md
@@ -7,6 +7,12 @@
   `AddEnvironmentVariableDetector`, `AddAttributes`, `AddService`, and
   `AddTelemetrySdk`.
   ([#1576](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1576))
+* Metrics API/SDK support is in an experimental state and is not recommended for
+  production use. All metric APIs have been marked with the `Obsolete`
+  attribute. See
+  [#1501](https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501)
+  for more information.
+  ([#1611](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1611))
 
 ## 1.0.0-rc1.1
 
diff --git a/src/OpenTelemetry/Metrics/Aggregators/Aggregator.cs b/src/OpenTelemetry/Metrics/Aggregators/Aggregator.cs
index 43d91734116..3b98c407bb2 100644
--- a/src/OpenTelemetry/Metrics/Aggregators/Aggregator.cs
+++ b/src/OpenTelemetry/Metrics/Aggregators/Aggregator.cs
@@ -24,6 +24,7 @@ namespace OpenTelemetry.Metrics.Aggregators
     /// Aggregator base class.
     /// </summary>
     /// <typeparam name="T">The type.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class Aggregator<T>
         where T : struct
     {
diff --git a/src/OpenTelemetry/Metrics/Aggregators/DoubleCounterSumAggregator.cs b/src/OpenTelemetry/Metrics/Aggregators/DoubleCounterSumAggregator.cs
index e00f74eeb9f..3b5e934da3b 100644
--- a/src/OpenTelemetry/Metrics/Aggregators/DoubleCounterSumAggregator.cs
+++ b/src/OpenTelemetry/Metrics/Aggregators/DoubleCounterSumAggregator.cs
@@ -23,6 +23,7 @@ namespace OpenTelemetry.Metrics.Aggregators
     /// <summary>
     /// Basic aggregator which calculates a Sum from individual measurements.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class DoubleCounterSumAggregator : Aggregator<double>
     {
         private double sum;
diff --git a/src/OpenTelemetry/Metrics/Aggregators/DoubleLastValueAggregator.cs b/src/OpenTelemetry/Metrics/Aggregators/DoubleLastValueAggregator.cs
index 5b9d54f4a67..87d49b6b7e2 100644
--- a/src/OpenTelemetry/Metrics/Aggregators/DoubleLastValueAggregator.cs
+++ b/src/OpenTelemetry/Metrics/Aggregators/DoubleLastValueAggregator.cs
@@ -23,6 +23,7 @@ namespace OpenTelemetry.Metrics.Aggregators
     /// <summary>
     /// Simple aggregator that only keeps the last value.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class DoubleLastValueAggregator : Aggregator<double>
     {
         private double value;
diff --git a/src/OpenTelemetry/Metrics/Aggregators/DoubleMeasureMinMaxSumCountAggregator.cs b/src/OpenTelemetry/Metrics/Aggregators/DoubleMeasureMinMaxSumCountAggregator.cs
index bf31691749f..e85af0c8d71 100644
--- a/src/OpenTelemetry/Metrics/Aggregators/DoubleMeasureMinMaxSumCountAggregator.cs
+++ b/src/OpenTelemetry/Metrics/Aggregators/DoubleMeasureMinMaxSumCountAggregator.cs
@@ -23,6 +23,7 @@ namespace OpenTelemetry.Metrics.Aggregators
     /// <summary>
     /// Aggregator which calculates summary (Min,Max,Sum,Count) from measures.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class DoubleMeasureMinMaxSumCountAggregator : Aggregator<double>
     {
         private DoubleSummary summary = new DoubleSummary();
diff --git a/src/OpenTelemetry/Metrics/Aggregators/Int64CounterSumAggregator.cs b/src/OpenTelemetry/Metrics/Aggregators/Int64CounterSumAggregator.cs
index cccdeab4b79..9577c49283e 100644
--- a/src/OpenTelemetry/Metrics/Aggregators/Int64CounterSumAggregator.cs
+++ b/src/OpenTelemetry/Metrics/Aggregators/Int64CounterSumAggregator.cs
@@ -23,6 +23,7 @@ namespace OpenTelemetry.Metrics.Aggregators
     /// <summary>
     /// Basic aggregator which calculates a Sum from individual measurements.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class Int64CounterSumAggregator : Aggregator<long>
     {
         private long sum;
diff --git a/src/OpenTelemetry/Metrics/Aggregators/Int64LastValueAggregator.cs b/src/OpenTelemetry/Metrics/Aggregators/Int64LastValueAggregator.cs
index 8061be8a469..617cba7edf1 100644
--- a/src/OpenTelemetry/Metrics/Aggregators/Int64LastValueAggregator.cs
+++ b/src/OpenTelemetry/Metrics/Aggregators/Int64LastValueAggregator.cs
@@ -23,6 +23,7 @@ namespace OpenTelemetry.Metrics.Aggregators
     /// <summary>
     /// Simple aggregator that only keeps the last value.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class Int64LastValueAggregator : Aggregator<long>
     {
         private long value;
diff --git a/src/OpenTelemetry/Metrics/Aggregators/Int64MeasureMinMaxSumCountAggregator.cs b/src/OpenTelemetry/Metrics/Aggregators/Int64MeasureMinMaxSumCountAggregator.cs
index 4570c99d407..bdc8285bc15 100644
--- a/src/OpenTelemetry/Metrics/Aggregators/Int64MeasureMinMaxSumCountAggregator.cs
+++ b/src/OpenTelemetry/Metrics/Aggregators/Int64MeasureMinMaxSumCountAggregator.cs
@@ -23,6 +23,7 @@ namespace OpenTelemetry.Metrics.Aggregators
     /// <summary>
     /// Aggregator which calculates summary (Min,Max,Sum,Count) from measures.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class Int64MeasureMinMaxSumCountAggregator : Aggregator<long>
     {
         private LongSummary summary = new LongSummary();
diff --git a/src/OpenTelemetry/Metrics/BoundCounterMetricSdkBase.cs b/src/OpenTelemetry/Metrics/BoundCounterMetricSdkBase.cs
index 04b8bbe51af..91e76457ca7 100644
--- a/src/OpenTelemetry/Metrics/BoundCounterMetricSdkBase.cs
+++ b/src/OpenTelemetry/Metrics/BoundCounterMetricSdkBase.cs
@@ -14,10 +14,12 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using OpenTelemetry.Metrics.Aggregators;
 
 namespace OpenTelemetry.Metrics
 {
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class BoundCounterMetricSdkBase<T> : BoundCounterMetric<T>
         where T : struct
     {
diff --git a/src/OpenTelemetry/Metrics/Export/AggregationType.cs b/src/OpenTelemetry/Metrics/Export/AggregationType.cs
index f66bb83f0ea..7683188468f 100644
--- a/src/OpenTelemetry/Metrics/Export/AggregationType.cs
+++ b/src/OpenTelemetry/Metrics/Export/AggregationType.cs
@@ -14,8 +14,11 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics.Export
 {
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public enum AggregationType
     {
         /// <summary>
diff --git a/src/OpenTelemetry/Metrics/Export/DoubleSumData.cs b/src/OpenTelemetry/Metrics/Export/DoubleSumData.cs
index f7e0df55e4b..68404e15e5b 100644
--- a/src/OpenTelemetry/Metrics/Export/DoubleSumData.cs
+++ b/src/OpenTelemetry/Metrics/Export/DoubleSumData.cs
@@ -14,8 +14,11 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics.Export
 {
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class DoubleSumData : MetricData
     {
         public double Sum { get; set; }
diff --git a/src/OpenTelemetry/Metrics/Export/DoubleSummaryData.cs b/src/OpenTelemetry/Metrics/Export/DoubleSummaryData.cs
index 0c4f7c7e853..ace9111f17c 100644
--- a/src/OpenTelemetry/Metrics/Export/DoubleSummaryData.cs
+++ b/src/OpenTelemetry/Metrics/Export/DoubleSummaryData.cs
@@ -14,8 +14,11 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics.Export
 {
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class DoubleSummaryData : MetricData
     {
         public long Count { get; set; }
diff --git a/src/OpenTelemetry/Metrics/Export/Int64SumData.cs b/src/OpenTelemetry/Metrics/Export/Int64SumData.cs
index aa03511e80a..cd2672d9308 100644
--- a/src/OpenTelemetry/Metrics/Export/Int64SumData.cs
+++ b/src/OpenTelemetry/Metrics/Export/Int64SumData.cs
@@ -14,8 +14,11 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics.Export
 {
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class Int64SumData : MetricData
     {
         public long Sum { get; set; }
diff --git a/src/OpenTelemetry/Metrics/Export/Int64SummaryData.cs b/src/OpenTelemetry/Metrics/Export/Int64SummaryData.cs
index 7475ffc7d94..c444f9cd67c 100644
--- a/src/OpenTelemetry/Metrics/Export/Int64SummaryData.cs
+++ b/src/OpenTelemetry/Metrics/Export/Int64SummaryData.cs
@@ -14,8 +14,11 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics.Export
 {
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class Int64SummaryData : MetricData
     {
         public long Count { get; set; }
diff --git a/src/OpenTelemetry/Metrics/Export/Metric.cs b/src/OpenTelemetry/Metrics/Export/Metric.cs
index 0c4f0fa0850..f18effbbb35 100644
--- a/src/OpenTelemetry/Metrics/Export/Metric.cs
+++ b/src/OpenTelemetry/Metrics/Export/Metric.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 
 namespace OpenTelemetry.Metrics.Export
@@ -21,6 +22,7 @@ namespace OpenTelemetry.Metrics.Export
     /// <summary>
     /// This class would evolve to become the export record.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class Metric
     {
         public Metric(
diff --git a/src/OpenTelemetry/Metrics/Export/MetricData.cs b/src/OpenTelemetry/Metrics/Export/MetricData.cs
index 2c4f55d78ba..4ea58e912e0 100644
--- a/src/OpenTelemetry/Metrics/Export/MetricData.cs
+++ b/src/OpenTelemetry/Metrics/Export/MetricData.cs
@@ -22,6 +22,7 @@ namespace OpenTelemetry.Metrics.Export
     /// <summary>
     /// MetricData base class.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class MetricData
     {
         public DateTime StartTimestamp { get; set; }
diff --git a/src/OpenTelemetry/Metrics/Export/MetricExporter.cs b/src/OpenTelemetry/Metrics/Export/MetricExporter.cs
index 0487d388ec4..4d774f7ad6c 100644
--- a/src/OpenTelemetry/Metrics/Export/MetricExporter.cs
+++ b/src/OpenTelemetry/Metrics/Export/MetricExporter.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
@@ -23,6 +24,7 @@ namespace OpenTelemetry.Metrics.Export
     /// <summary>
     /// MetricExporter base class.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class MetricExporter
     {
         /// <summary>
diff --git a/src/OpenTelemetry/Metrics/Export/MetricProcessor.cs b/src/OpenTelemetry/Metrics/Export/MetricProcessor.cs
index 497a8278aba..ffe7d6aa870 100644
--- a/src/OpenTelemetry/Metrics/Export/MetricProcessor.cs
+++ b/src/OpenTelemetry/Metrics/Export/MetricProcessor.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 
 namespace OpenTelemetry.Metrics.Export
@@ -21,6 +22,7 @@ namespace OpenTelemetry.Metrics.Export
     /// <summary>
     /// MetricProcessor base class.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class MetricProcessor
     {
         /// <summary>
diff --git a/src/OpenTelemetry/Metrics/Export/UngroupedBatcher.cs b/src/OpenTelemetry/Metrics/Export/UngroupedBatcher.cs
index eb3780103a2..1996431d229 100644
--- a/src/OpenTelemetry/Metrics/Export/UngroupedBatcher.cs
+++ b/src/OpenTelemetry/Metrics/Export/UngroupedBatcher.cs
@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 using OpenTelemetry.Internal;
 
@@ -22,6 +23,7 @@ namespace OpenTelemetry.Metrics.Export
     /// <summary>
     /// Batcher which retains all dimensions/labels.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class UngroupedBatcher : MetricProcessor
     {
         private List<Metric> metrics;
diff --git a/src/OpenTelemetry/Metrics/MeterProviderBuilder.cs b/src/OpenTelemetry/Metrics/MeterProviderBuilder.cs
index 32ceeb8971a..4d2b1904f5f 100644
--- a/src/OpenTelemetry/Metrics/MeterProviderBuilder.cs
+++ b/src/OpenTelemetry/Metrics/MeterProviderBuilder.cs
@@ -25,6 +25,7 @@ namespace OpenTelemetry.Metrics
     /// <summary>
     /// Build MeterProvider with Exporter, Processor and PushInterval.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class MeterProviderBuilder
     {
         private static readonly TimeSpan DefaultPushInterval = TimeSpan.FromSeconds(60);
diff --git a/src/OpenTelemetry/OpenTelemetry.csproj b/src/OpenTelemetry/OpenTelemetry.csproj
index 36ceb4b2b5a..8f8ae046559 100644
--- a/src/OpenTelemetry/OpenTelemetry.csproj
+++ b/src/OpenTelemetry/OpenTelemetry.csproj
@@ -5,7 +5,7 @@
     <!--
     TODO: Disable this exception, and actually do document all public API.
     -->
-    <NoWarn>$(NoWarn),1591</NoWarn>
+    <NoWarn>$(NoWarn),1591,CS0618</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/test/OpenTelemetry.Exporter.Prometheus.Tests/OpenTelemetry.Exporter.Prometheus.Tests.csproj b/test/OpenTelemetry.Exporter.Prometheus.Tests/OpenTelemetry.Exporter.Prometheus.Tests.csproj
index 19b25ee652c..09e4ef3531e 100644
--- a/test/OpenTelemetry.Exporter.Prometheus.Tests/OpenTelemetry.Exporter.Prometheus.Tests.csproj
+++ b/test/OpenTelemetry.Exporter.Prometheus.Tests/OpenTelemetry.Exporter.Prometheus.Tests.csproj
@@ -5,6 +5,7 @@
     <TargetFrameworks>netcoreapp2.1;netcoreapp3.1;net5.0</TargetFrameworks>
     <TargetFrameworks Condition="$(OS) == 'Windows_NT'">$(TargetFrameworks);net452;net46</TargetFrameworks>
     <IsPackable>false</IsPackable>
+    <NoWarn>$(NoWarn),CS0618</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/test/OpenTelemetry.Tests/OpenTelemetry.Tests.csproj b/test/OpenTelemetry.Tests/OpenTelemetry.Tests.csproj
index 8c77f77b1ae..fd0acda5810 100644
--- a/test/OpenTelemetry.Tests/OpenTelemetry.Tests.csproj
+++ b/test/OpenTelemetry.Tests/OpenTelemetry.Tests.csproj
@@ -3,6 +3,7 @@
     <Description>Unit test project for OpenTelemetry</Description>
     <TargetFrameworks>netcoreapp2.1;netcoreapp3.1;net5.0</TargetFrameworks>
     <TargetFrameworks Condition="$(OS) == 'Windows_NT'">$(TargetFrameworks);net46;net452</TargetFrameworks>
+    <NoWarn>$(NoWarn),CS0618</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>