diff --git a/clientsession.go b/clientsession.go
index 8d0da87..11de3fc 100644
--- a/clientsession.go
+++ b/clientsession.go
@@ -46,6 +46,8 @@ var (
 )
 
 type ClientSession struct {
+	roomJoinTime int64
+
 	running   int32
 	hub       *Hub
 	privateId string
@@ -289,12 +291,21 @@ func (s *ClientSession) IsExpired(now time.Time) bool {
 
 func (s *ClientSession) SetRoom(room *Room) {
 	atomic.StorePointer(&s.room, unsafe.Pointer(room))
+	if room != nil {
+		atomic.StoreInt64(&s.roomJoinTime, time.Now().UnixNano())
+	} else {
+		atomic.StoreInt64(&s.roomJoinTime, 0)
+	}
 }
 
 func (s *ClientSession) GetRoom() *Room {
 	return (*Room)(atomic.LoadPointer(&s.room))
 }
 
+func (s *ClientSession) getRoomJoinTime() time.Time {
+	return time.Unix(0, atomic.LoadInt64(&s.roomJoinTime))
+}
+
 func (s *ClientSession) releaseMcuObjects() {
 	if len(s.publishers) > 0 {
 		go func(publishers map[string]McuPublisher) {
@@ -815,6 +826,13 @@ func (s *ClientSession) processNatsMessage(msg *NatsMessage) *ServerMessage {
 				// TODO(jojo): Only send all users if current session id has
 				// changed its "inCall" flag to true.
 				m.Changed = nil
+			} else if msg.Message.Event.Target == "room" {
+				// Can happen mostly during tests where an older room NATS message
+				// could be received by a subscriber that joined after it was sent.
+				if msg.SendTime.Before(s.getRoomJoinTime()) {
+					log.Printf("Message %+v was sent before room was joined, ignoring", msg.Message)
+					return nil
+				}
 			}
 		}
 
diff --git a/natsclient.go b/natsclient.go
index 6925b57..a9e07ae 100644
--- a/natsclient.go
+++ b/natsclient.go
@@ -38,6 +38,8 @@ const (
 )
 
 type NatsMessage struct {
+	SendTime time.Time `json:"sendtime"`
+
 	Type string `json:"type"`
 
 	Message *ServerMessage `json:"message,omitempty"`
@@ -150,16 +152,18 @@ func (c *natsClient) PublishNats(subject string, message *NatsMessage) error {
 
 func (c *natsClient) PublishMessage(subject string, message *ServerMessage) error {
 	msg := &NatsMessage{
-		Type:    "message",
-		Message: message,
+		SendTime: time.Now(),
+		Type:     "message",
+		Message:  message,
 	}
 	return c.PublishNats(subject, msg)
 }
 
 func (c *natsClient) PublishBackendServerRoomRequest(subject string, message *BackendServerRoomRequest) error {
 	msg := &NatsMessage{
-		Type: "room",
-		Room: message,
+		SendTime: time.Now(),
+		Type:     "room",
+		Room:     message,
 	}
 	return c.PublishNats(subject, msg)
 }
diff --git a/natsclient_loopback.go b/natsclient_loopback.go
index 7a7d819..aaa1699 100644
--- a/natsclient_loopback.go
+++ b/natsclient_loopback.go
@@ -27,6 +27,7 @@ import (
 	"log"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/nats-io/nats.go"
 )
@@ -175,16 +176,18 @@ func (c *LoopbackNatsClient) PublishNats(subject string, message *NatsMessage) e
 
 func (c *LoopbackNatsClient) PublishMessage(subject string, message *ServerMessage) error {
 	msg := &NatsMessage{
-		Type:    "message",
-		Message: message,
+		SendTime: time.Now(),
+		Type:     "message",
+		Message:  message,
 	}
 	return c.PublishNats(subject, msg)
 }
 
 func (c *LoopbackNatsClient) PublishBackendServerRoomRequest(subject string, message *BackendServerRoomRequest) error {
 	msg := &NatsMessage{
-		Type: "room",
-		Room: message,
+		SendTime: time.Now(),
+		Type:     "room",
+		Room:     message,
 	}
 	return c.PublishNats(subject, msg)
 }