diff --git a/charts/vald/templates/agent/readreplica/svc.yaml b/charts/vald/templates/agent/readreplica/svc.yaml
index 441c00c5cb2..e4d94b78d49 100644
--- a/charts/vald/templates/agent/readreplica/svc.yaml
+++ b/charts/vald/templates/agent/readreplica/svc.yaml
@@ -50,6 +50,7 @@ spec:
     app: {{ $readreplica.name }}-{{ $id }}
     app.kubernetes.io/name: {{ $valdname }}
   type: ClusterIP
+  clusterIP: None
   {{- if $agent.externalTrafficPolicy }}
   externalTrafficPolicy: {{ $agent.externalTrafficPolicy }}
   {{- end }}
diff --git a/charts/vald/templates/gateway/lb/configmap.yaml b/charts/vald/templates/gateway/lb/configmap.yaml
index 430040b9296..6be0a7a5060 100644
--- a/charts/vald/templates/gateway/lb/configmap.yaml
+++ b/charts/vald/templates/gateway/lb/configmap.yaml
@@ -16,6 +16,8 @@
 {{- $gateway := .Values.gateway.lb -}}
 {{- $agent := .Values.agent -}}
 {{- $discoverer := .Values.discoverer -}}
+{{- $readreplica := .Values.agent.readreplica -}}
+{{- $release := .Release -}}
 {{- if $gateway.enabled }}
 apiVersion: v1
 kind: ConfigMap
@@ -49,6 +51,7 @@ data:
       agent_namespace: {{ $gateway.gateway_config.agent_namespace | quote }}
       node_name: {{ $gateway.gateway_config.node_name | quote }}
       index_replica: {{ $gateway.gateway_config.index_replica }}
+      readreplica_replicas: {{ $readreplica.replica }}
       discoverer:
         duration: {{ $gateway.gateway_config.discoverer.duration }}
         client:
@@ -64,4 +67,20 @@ data:
         agent_client_options:
           {{- include "vald.grpc.client.addrs" (dict "Valued" $gateway.gateway_config.discoverer.agent_client_options.addrs) | nindent 10 }}
           {{- include "vald.grpc.client" (dict "Values" $gateway.gateway_config.discoverer.agent_client_options "default" .Values.defaults.grpc.client) | nindent 10 }}
+      {{- if $readreplica.enabled }}
+      read_replica_client:
+        client:
+          {{- $discovererClient := $gateway.gateway_config.discoverer.client }}
+          {{- $readReplicaPort := $agent.server_config.servers.grpc.port }}
+          {{- $defaultReadReplicaPort := default .Values.defaults.server_config.servers.grpc.port $readReplicaPort }}
+          {{- $readReplicaAddrs := list }}
+          {{- range $i := until (int $agent.minReplicas) }}
+            {{- $addr := printf "%s-%d.%s.svc.cluster.local:%d" $readreplica.name $i $release.Namespace (int64 $defaultReadReplicaPort) }}
+            {{- $readReplicaAddrs = append $readReplicaAddrs $addr }}
+          {{- end }}
+          {{- $readReplicaAddrs := dict "Values" $discovererClient.addrs "default" $readReplicaAddrs }}
+          {{- include "vald.grpc.client.addrs" $readReplicaAddrs | nindent 10 }}
+          {{- $readReplicaGRPCclient := dict "Values" $discovererClient "default" .Values.defaults.grpc.client }}
+          {{- include "vald.grpc.client" $readReplicaGRPCclient | nindent 10 }}
+      {{- end }}
 {{- end }}
diff --git a/internal/client/v1/client/discoverer/discover.go b/internal/client/v1/client/discoverer/discover.go
index 89a43f2a8cb..43fd6f526ba 100644
--- a/internal/client/v1/client/discoverer/discover.go
+++ b/internal/client/v1/client/discoverer/discover.go
@@ -37,7 +37,9 @@ import (
 type Client interface {
 	Start(ctx context.Context) (<-chan error, error)
 	GetAddrs(ctx context.Context) []string
+	GetReadAddrs(ctx context.Context) []string
 	GetClient() grpc.Client
+	GetReadClient() grpc.Client
 }
 
 type client struct {
@@ -56,6 +58,11 @@ type client struct {
 	name         string
 	namespace    string
 	nodeName     string
+	// read replica related below
+	readClient          grpc.Client
+	readAddrs           atomic.Pointer[[]string]
+	readReplicaReplicas uint64
+	roundRobin          atomic.Uint64
 }
 
 func New(opts ...Option) (d Client, err error) {
@@ -74,6 +81,14 @@ func (c *client) Start(ctx context.Context) (<-chan error, error) {
 		return nil, err
 	}
 
+	var rrech <-chan error
+	if c.readClient != nil {
+		rrech, err = c.readClient.StartConnectionMonitor(ctx)
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	ech := make(chan error, 100)
 	addrs, err := c.dnsDiscovery(ctx, ech)
 	if err != nil {
@@ -134,6 +149,7 @@ func (c *client) Start(ctx context.Context) (<-chan error, error) {
 				return finalize()
 			case err = <-dech:
 			case err = <-aech:
+			case err = <-rrech:
 			case <-dt.C:
 				err = c.discover(ctx, ech)
 			}
@@ -168,12 +184,45 @@ func (c *client) GetAddrs(ctx context.Context) (addrs []string) {
 	return addrs
 }
 
+func (c *client) GetReadAddrs(ctx context.Context) []string {
+	a := c.readAddrs.Load()
+	if a == nil {
+		return nil
+	}
+	return *a
+}
+
 func (c *client) GetClient() grpc.Client {
 	return c.client
 }
 
+func (c *client) GetReadClient() grpc.Client {
+	// read replica
+	// 1. primary + svc cluster IP *n でここで比率を見て呼び分ける
+	//    read replicaのreplica数がHPAなどで高速に変動する場合に、実装がシンプルそうなのでこちらが良さそう
+	// 2. primary + ipsで単純にラウンドロビン
+
+	// round robin with c.client and c.readClient everytime it's called
+	// with a ratio of primary + read replica deployment replicas
+	// TODO: is this atomic operation really worth it?
+	var new uint64
+	for {
+		cur := c.roundRobin.Load()
+		new = (cur + 1) % (c.readReplicaReplicas + 1)
+		if c.roundRobin.CompareAndSwap(cur, new) {
+			break
+		}
+	}
+	if new == 0 || c.readClient == nil {
+		return c.client
+		// return c.readClient // DEBUG:
+	}
+	return c.readClient
+}
+
 func (c *client) connect(ctx context.Context, addr string) (err error) {
 	if c.autoconn && c.client != nil {
+		// FIXME: この中で重複管理されている
 		_, err = c.client.Connect(ctx, addr)
 		if err != nil {
 			return err
@@ -323,6 +372,7 @@ func (c *client) discoverAddrs(ctx context.Context, nodes *payload.Info_Nodes, e
 					len(node.GetPods().GetPods()) > i &&
 					len(node.GetPods().GetPods()[i].GetIp()) != 0 {
 					addr := net.JoinHostPort(node.GetPods().GetPods()[i].GetIp(), uint16(c.port))
+					// FIXME: ここで実際にgrpcサーバーへ接続する
 					if err = c.connect(ctx, addr); err != nil {
 						select {
 						case <-ctx.Done():
diff --git a/internal/client/v1/client/discoverer/option.go b/internal/client/v1/client/discoverer/option.go
index aca62c61f2d..23bdff62296 100644
--- a/internal/client/v1/client/discoverer/option.go
+++ b/internal/client/v1/client/discoverer/option.go
@@ -68,6 +68,13 @@ func WithDiscovererClient(gc grpc.Client) Option {
 	}
 }
 
+func WithReadReplicaClient(gc grpc.Client) Option {
+	return func(c *client) error {
+		c.readClient = gc
+		return nil
+	}
+}
+
 func WithDiscoverDuration(dur string) Option {
 	return func(c *client) error {
 		d, err := timeutil.Parse(dur)
@@ -142,3 +149,10 @@ func WithErrGroup(eg errgroup.Group) Option {
 		return nil
 	}
 }
+
+func WithReadReplicaReplicas(num uint64) Option {
+	return func(c *client) error {
+		c.readReplicaReplicas = num
+		return nil
+	}
+}
diff --git a/internal/config/lb.go b/internal/config/lb.go
index 0e6a429f2f4..467098e43a3 100644
--- a/internal/config/lb.go
+++ b/internal/config/lb.go
@@ -37,6 +37,12 @@ type LB struct {
 	// IndexReplica represents index replication count
 	IndexReplica int `json:"index_replica" yaml:"index_replica"`
 
+	// ReadReplicaReplicas represents replica count of read replica Deployment
+	ReadReplicaReplicas uint64 `json:"read_replica_replicas" yaml:"read_replica_replicas"`
+
+	// ReadReplicaClient represents read replica client configuration
+	ReadReplicaClient ReadReplicaClient `json:"read_replica_client" yaml:"read_replica_client"`
+
 	// Discoverer represent agent discoverer service configuration
 	Discoverer *DiscovererClient `json:"discoverer" yaml:"discoverer"`
 
@@ -56,3 +62,26 @@ func (g *LB) Bind() *LB {
 	}
 	return g
 }
+
+// ReadReplicaClient
+type ReadReplicaClient struct {
+	Duration           string      `json:"duration"             yaml:"duration"`
+	Client             *GRPCClient `json:"client"               yaml:"client"`
+	AgentClientOptions *GRPCClient `json:"agent_client_options" yaml:"agent_client_options"`
+}
+
+// Bind binds the actual data from the ReadReplicaClient receiver field.
+func (d *ReadReplicaClient) Bind() *ReadReplicaClient {
+	d.Duration = GetActualValue(d.Duration)
+	if d.Client != nil {
+		d.Client.Bind()
+	} else {
+		d.Client = newGRPCClientConfig()
+	}
+	if d.AgentClientOptions != nil {
+		d.AgentClientOptions.Bind()
+	} else {
+		d.AgentClientOptions = newGRPCClientConfig()
+	}
+	return d
+}
diff --git a/pkg/gateway/lb/handler/grpc/aggregation.go b/pkg/gateway/lb/handler/grpc/aggregation.go
index 58f749eee04..26b51bf5472 100644
--- a/pkg/gateway/lb/handler/grpc/aggregation.go
+++ b/pkg/gateway/lb/handler/grpc/aggregation.go
@@ -33,6 +33,7 @@ import (
 	"github.com/vdaas/vald/internal/net/grpc/status"
 	"github.com/vdaas/vald/internal/observability/trace"
 	"github.com/vdaas/vald/internal/sync"
+	"github.com/vdaas/vald/pkg/gateway/lb/service"
 )
 
 type Aggregator interface {
@@ -68,7 +69,7 @@ func (s *server) aggregationSearch(ctx context.Context, aggr Aggregator, cfg *pa
 
 	ctx, cancel := context.WithTimeout(ctx, timeout)
 	aggr.Start(ctx)
-	err = s.gateway.BroadCast(ctx, func(ctx context.Context, target string, vc vald.Client, copts ...grpc.CallOption) error {
+	err = s.gateway.BroadCast(ctx, service.READ, func(ctx context.Context, target string, vc vald.Client, copts ...grpc.CallOption) error {
 		sctx, sspan := trace.StartSpan(grpc.WrapGRPCMethod(ctx, "BroadCast/"+target), apiName+"/aggregationSearch/"+target)
 		defer func() {
 			if sspan != nil {
diff --git a/pkg/gateway/lb/handler/grpc/handler.go b/pkg/gateway/lb/handler/grpc/handler.go
index e8fde265a6a..95fa86b1dc0 100644
--- a/pkg/gateway/lb/handler/grpc/handler.go
+++ b/pkg/gateway/lb/handler/grpc/handler.go
@@ -95,7 +95,7 @@ func (s *server) exists(ctx context.Context, uuid string) (id *payload.Object_ID
 		defer close(ich)
 		defer close(ech)
 		var once sync.Once
-		ech <- s.gateway.BroadCast(ctx, func(ctx context.Context, target string, vc vald.Client, copts ...grpc.CallOption) error {
+		ech <- s.gateway.BroadCast(ctx, service.READ, func(ctx context.Context, target string, vc vald.Client, copts ...grpc.CallOption) error {
 			sctx, sspan := trace.StartSpan(grpc.WrapGRPCMethod(ctx, "BroadCast/"+target), apiName+"/exists/BroadCast/"+target)
 			defer func() {
 				if sspan != nil {
@@ -1653,7 +1653,7 @@ func (s *server) Update(ctx context.Context, req *payload.Update_Request) (res *
 				Ips:  make([]string, 0, s.replica),
 			}
 		)
-		err = s.gateway.BroadCast(ctx, func(ctx context.Context, target string, vc vald.Client, copts ...grpc.CallOption) (err error) {
+		err = s.gateway.BroadCast(ctx, service.WRITE, func(ctx context.Context, target string, vc vald.Client, copts ...grpc.CallOption) (err error) {
 			ctx, span := trace.StartSpan(grpc.WrapGRPCMethod(ctx, "BroadCast/"+target), apiName+"/"+vald.UpdateRPCName+"/"+target)
 			defer func() {
 				if span != nil {
@@ -2562,7 +2562,7 @@ func (s *server) Remove(ctx context.Context, req *payload.Remove_Request) (locs
 		Ips:  make([]string, 0, s.replica),
 	}
 	ls := make([]string, 0, s.replica)
-	err = s.gateway.BroadCast(ctx, func(ctx context.Context, target string, vc vald.Client, copts ...grpc.CallOption) (err error) {
+	err = s.gateway.BroadCast(ctx, service.WRITE, func(ctx context.Context, target string, vc vald.Client, copts ...grpc.CallOption) (err error) {
 		ctx, span := trace.StartSpan(grpc.WrapGRPCMethod(ctx, "BroadCast/"+target), apiName+"/"+vald.RemoveRPCName+"/"+target)
 		defer func() {
 			if span != nil {
@@ -2778,7 +2778,7 @@ func (s *server) RemoveByTimestamp(ctx context.Context, req *payload.Remove_Time
 	visited := make(map[string]int) // map[uuid: position of locs]
 	locs = new(payload.Object_Locations)
 
-	err := s.gateway.BroadCast(ctx, func(ctx context.Context, target string, vc vald.Client, copts ...grpc.CallOption) (err error) {
+	err := s.gateway.BroadCast(ctx, service.WRITE, func(ctx context.Context, target string, vc vald.Client, copts ...grpc.CallOption) (err error) {
 		sctx, sspan := trace.StartSpan(grpc.WithGRPCMethod(ctx, "BroadCast/"+target), apiName+"/removeByTimestamp/BroadCast/"+target)
 		defer func() {
 			if sspan != nil {
@@ -2905,7 +2905,7 @@ func (s *server) getObject(ctx context.Context, uuid string) (vec *payload.Objec
 		defer close(vch)
 		defer close(ech)
 		var once sync.Once
-		ech <- s.gateway.BroadCast(ctx, func(ctx context.Context, target string, vc vald.Client, copts ...grpc.CallOption) error {
+		ech <- s.gateway.BroadCast(ctx, service.READ, func(ctx context.Context, target string, vc vald.Client, copts ...grpc.CallOption) error {
 			sctx, sspan := trace.StartSpan(grpc.WrapGRPCMethod(ctx, "BroadCast/"+target), apiName+"/getObject/BroadCast/"+target)
 			defer func() {
 				if sspan != nil {
@@ -3143,7 +3143,7 @@ func (s *server) StreamListObject(req *payload.Object_List_Request, stream vald.
 	defer cancel()
 
 	var rmu, smu sync.Mutex
-	err := s.gateway.BroadCast(ctx, func(ctx context.Context, target string, vc vald.Client, copts ...grpc.CallOption) error {
+	err := s.gateway.BroadCast(ctx, service.READ, func(ctx context.Context, target string, vc vald.Client, copts ...grpc.CallOption) error {
 		ctx, sspan := trace.StartSpan(grpc.WrapGRPCMethod(ctx, "BroadCast/"+target), apiName+"/"+vald.StreamListObjectRPCName+"/"+target)
 		defer func() {
 			if sspan != nil {
diff --git a/pkg/gateway/lb/service/gateway.go b/pkg/gateway/lb/service/gateway.go
index 7d32364df0c..b3ffdf5a9ab 100644
--- a/pkg/gateway/lb/service/gateway.go
+++ b/pkg/gateway/lb/service/gateway.go
@@ -37,10 +37,16 @@ type Gateway interface {
 	Addrs(ctx context.Context) []string
 	DoMulti(ctx context.Context, num int,
 		f func(ctx context.Context, target string, ac vald.Client, copts ...grpc.CallOption) error) error
-	BroadCast(ctx context.Context,
+	BroadCast(ctx context.Context, kind BroadCastKind,
 		f func(ctx context.Context, target string, ac vald.Client, copts ...grpc.CallOption) error) error
 }
 
+type BroadCastKind int
+const (
+	READ BroadCastKind = iota
+	WRITE
+)
+
 type gateway struct {
 	client discoverer.Client
 	eg     errgroup.Group
@@ -60,7 +66,9 @@ func (g *gateway) Start(ctx context.Context) (<-chan error, error) {
 	return g.client.Start(ctx)
 }
 
-func (g *gateway) BroadCast(ctx context.Context,
+// FIXME: そもそも呼ばれているメソッドがread系かwrite系かをどこかで判断する必要があるが、
+// 今後もメソッドは増えていくのだからBroadCastとBroadCastReadみたいに分けて、呼び出し側で判断するべき
+func (g *gateway) BroadCast(ctx context.Context, kind BroadCastKind,
 	f func(ctx context.Context, target string, ac vald.Client, copts ...grpc.CallOption) error,
 ) (err error) {
 	fctx, span := trace.StartSpan(ctx, "vald/gateway-lb/service/Gateway.BroadCast")
@@ -69,7 +77,20 @@ func (g *gateway) BroadCast(ctx context.Context,
 			span.End()
 		}
 	}()
-	return g.client.GetClient().RangeConcurrent(fctx, -1, func(ictx context.Context,
+
+	// select read or write clinet which is connected to primary agent or read replica agent
+	// GetReadClient includes the client to the primary agent so
+	// it works even when there is no read replica
+	var client grpc.Client
+	switch kind {
+	case READ:
+		client = g.client.GetReadClient()
+	case WRITE:
+		client = g.client.GetClient()
+	}
+
+	// FIXME: broadcastはsvc経由でロードバランスされてるっぽい
+	return client.RangeConcurrent(fctx, -1, func(ictx context.Context,
 		addr string, conn *grpc.ClientConn, copts ...grpc.CallOption,
 	) (err error) {
 		select {
@@ -85,6 +106,7 @@ func (g *gateway) BroadCast(ctx context.Context,
 	})
 }
 
+// DoMultiはWrite系しか使用しないので、普通にGetClientしていれば良い。現状Update or Insertのみ
 func (g *gateway) DoMulti(ctx context.Context, num int,
 	f func(ctx context.Context, target string, ac vald.Client, copts ...grpc.CallOption) error,
 ) (err error) {
diff --git a/pkg/gateway/lb/usecase/vald.go b/pkg/gateway/lb/usecase/vald.go
index 4b2eadef88c..27bf60f39bc 100644
--- a/pkg/gateway/lb/usecase/vald.go
+++ b/pkg/gateway/lb/usecase/vald.go
@@ -55,6 +55,16 @@ func New(cfg *config.Data) (r runner.Runner, err error) {
 	if err != nil {
 		return nil, err
 	}
+
+	rrOpts, err := cfg.Gateway.ReadReplicaClient.Client.Opts()
+	if err != nil {
+		return nil, err
+	}
+	rrOpts = append(rrOpts,
+		grpc.WithErrGroup(eg),
+		grpc.WithConnectionPoolSize(int(cfg.Gateway.ReadReplicaReplicas)),
+	)
+
 	// skipcq: CRT-D0001
 	dopts := append(
 		cOpts,
@@ -75,9 +85,11 @@ func New(cfg *config.Data) (r runner.Runner, err error) {
 		discoverer.WithPort(cfg.Gateway.AgentPort),
 		discoverer.WithServiceDNSARecord(cfg.Gateway.AgentDNS),
 		discoverer.WithDiscovererClient(grpc.New(dopts...)),
+		discoverer.WithReadReplicaClient(grpc.New(rrOpts...)),
 		discoverer.WithDiscoverDuration(cfg.Gateway.Discoverer.Duration),
 		discoverer.WithOptions(aopts...),
 		discoverer.WithNodeName(cfg.Gateway.NodeName),
+		discoverer.WithReadReplicaReplicas(cfg.Gateway.ReadReplicaReplicas),
 	)
 	if err != nil {
 		return nil, err