diff --git a/CHANGES.md b/CHANGES.md
index 05c3720a1b..8fe435c716 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -19,6 +19,7 @@ Bug Fixes
 ---------
 * [#1183](https://github.com/java-native-access/jna/pull/1183): `c.s.j.p.win32.WinDef.CHARByReference#getValue` should only read one byte - [@dbwiddis](https://github.com/dbwiddis).
 * [#1184](https://github.com/java-native-access/jna/pull/1184): `c.s.j.p.win32.WinDef.ULONGLONG` should always be 8 bytes - [@dbwiddis](https://github.com/dbwiddis).
+* [#1196](https://github.com/java-native-access/jna/pull/1196): `c.s.j.p.win32.WinNT.LARGE_INTEGER` needs to populate both union fields - [@dbwiddis](https://github.com/dbwiddis).
 
 Release 5.5.0
 =============
diff --git a/contrib/platform/src/com/sun/jna/platform/win32/WinNT.java b/contrib/platform/src/com/sun/jna/platform/win32/WinNT.java
index aa3f79eb67..2a28d33a3b 100644
--- a/contrib/platform/src/com/sun/jna/platform/win32/WinNT.java
+++ b/contrib/platform/src/com/sun/jna/platform/win32/WinNT.java
@@ -1220,6 +1220,12 @@ public UNION(long value) {
                 this.lh = new LowHigh(value);
             }
 
+            @Override
+            public void read() {
+                readField("lh");
+                readField("value");
+            }
+
             public long longValue() {
                 return value;
             }
diff --git a/contrib/platform/test/com/sun/jna/platform/win32/WinNTTypesTest.java b/contrib/platform/test/com/sun/jna/platform/win32/WinNTTypesTest.java
index 2eff9335f4..2bdac2b7c5 100644
--- a/contrib/platform/test/com/sun/jna/platform/win32/WinNTTypesTest.java
+++ b/contrib/platform/test/com/sun/jna/platform/win32/WinNTTypesTest.java
@@ -25,10 +25,24 @@
 
 import org.junit.Test;
 
+import com.sun.jna.Memory;
+import com.sun.jna.Pointer;
+import com.sun.jna.Structure;
+import com.sun.jna.Structure.FieldOrder;
 import com.sun.jna.platform.win32.WinNT.LARGE_INTEGER;
 
 public class WinNTTypesTest extends AbstractWin32TestSupport {
 
+    @FieldOrder({ "largeInt" })
+    public class LargeIntegerStruct extends Structure {
+        public LARGE_INTEGER largeInt;
+
+        public LargeIntegerStruct(Pointer p) {
+            super(p);
+            read();
+        }
+    }
+
     @Test
     public void testLargeIntegerLowHighLongValue() {
         for (long expected : new long[]{
@@ -47,12 +61,21 @@ public void testLargeIntegerUnionLongValue() {
             0L,
             Long.MAX_VALUE, Integer.MAX_VALUE, Short.MAX_VALUE, Byte.MAX_VALUE
         }) {
+            // test with long constructor
             LARGE_INTEGER large = new LARGE_INTEGER(expected);
             assertEquals("Mismatched large value", expected, large.getValue());
 
             LARGE_INTEGER.LowHigh loHi = new LARGE_INTEGER.LowHigh(expected);
             assertEquals("Mismatched low part", loHi.LowPart, large.getLow());
             assertEquals("Mismatched high part", loHi.HighPart, large.getHigh());
+
+            // test populated from memory
+            Memory m = new Memory(Long.BYTES);
+            m.setLong(0, expected);
+            large = new LargeIntegerStruct(m).largeInt;
+            assertEquals("Mismatched large value in struct", expected, large.getValue());
+            assertEquals("Mismatched low part in struct", loHi.LowPart, large.getLow());
+            assertEquals("Mismatched high part in struct", loHi.HighPart, large.getHigh());
         }
     }
 }