diff --git a/rpc/subscription.go b/rpc/subscription.go
index 6ce7befa1..6bbb6f75d 100644
--- a/rpc/subscription.go
+++ b/rpc/subscription.go
@@ -52,9 +52,10 @@ type notifierKey struct{}
 // Server callbacks use the notifier to send notifications.
 type Notifier struct {
 	codec    ServerCodec
-	subMu    sync.RWMutex // guards active and inactive maps
+	subMu    sync.Mutex
 	active   map[ID]*Subscription
 	inactive map[ID]*Subscription
+	buffer   map[ID][]interface{} // unsent notifications of inactive subscriptions
 }
 
 // newNotifier creates a new notifier that can be used to send subscription
@@ -64,6 +65,7 @@ func newNotifier(codec ServerCodec) *Notifier {
 		codec:    codec,
 		active:   make(map[ID]*Subscription),
 		inactive: make(map[ID]*Subscription),
+		buffer:   make(map[ID][]interface{}),
 	}
 }
 
@@ -88,20 +90,26 @@ func (n *Notifier) CreateSubscription() *Subscription {
 // Notify sends a notification to the client with the given data as payload.
 // If an error occurs the RPC connection is closed and the error is returned.
 func (n *Notifier) Notify(id ID, data interface{}) error {
-	n.subMu.RLock()
-	defer n.subMu.RUnlock()
+	n.subMu.Lock()
+	defer n.subMu.Unlock()
 
-	sub, active := n.active[id]
-	if active {
-		notification := n.codec.CreateNotification(string(id), sub.namespace, data)
-		if err := n.codec.Write(notification); err != nil {
-			n.codec.Close()
-			return err
-		}
+	if sub, active := n.active[id]; active {
+		n.send(sub, data)
+	} else {
+		n.buffer[id] = append(n.buffer[id], data)
 	}
 	return nil
 }
 
+func (n *Notifier) send(sub *Subscription, data interface{}) error {
+	notification := n.codec.CreateNotification(string(sub.ID), sub.namespace, data)
+	err := n.codec.Write(notification)
+	if err != nil {
+		n.codec.Close()
+	}
+	return err
+}
+
 // Closed returns a channel that is closed when the RPC connection is closed.
 func (n *Notifier) Closed() <-chan interface{} {
 	return n.codec.Closed()
@@ -127,9 +135,15 @@ func (n *Notifier) unsubscribe(id ID) error {
 func (n *Notifier) activate(id ID, namespace string) {
 	n.subMu.Lock()
 	defer n.subMu.Unlock()
+
 	if sub, found := n.inactive[id]; found {
 		sub.namespace = namespace
 		n.active[id] = sub
 		delete(n.inactive, id)
+		// Send buffered notifications.
+		for _, data := range n.buffer[id] {
+			n.send(sub, data)
+		}
+		delete(n.buffer, id)
 	}
 }
diff --git a/rpc/subscription_test.go b/rpc/subscription_test.go
index 0ba177e63..24febc919 100644
--- a/rpc/subscription_test.go
+++ b/rpc/subscription_test.go
@@ -27,9 +27,8 @@ import (
 )
 
 type NotificationTestService struct {
-	mu           sync.Mutex
-	unsubscribed bool
-
+	mu                      sync.Mutex
+	unsubscribed            chan string
 	gotHangSubscriptionReq  chan struct{}
 	unblockHangSubscription chan struct{}
 }
@@ -38,16 +37,10 @@ func (s *NotificationTestService) Echo(i int) int {
 	return i
 }
 
-func (s *NotificationTestService) wasUnsubCallbackCalled() bool {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-	return s.unsubscribed
-}
-
 func (s *NotificationTestService) Unsubscribe(subid string) {
-	s.mu.Lock()
-	s.unsubscribed = true
-	s.mu.Unlock()
+	if s.unsubscribed != nil {
+		s.unsubscribed <- subid
+	}
 }
 
 func (s *NotificationTestService) SomeSubscription(ctx context.Context, n, val int) (*Subscription, error) {
@@ -65,7 +58,6 @@ func (s *NotificationTestService) SomeSubscription(ctx context.Context, n, val i
 		// test expects n events, if we begin sending event immediately some events
 		// will probably be dropped since the subscription ID might not be send to
 		// the client.
-		time.Sleep(5 * time.Second)
 		for i := 0; i < n; i++ {
 			if err := notifier.Notify(subscription.ID, val+i); err != nil {
 				return
@@ -74,13 +66,10 @@ func (s *NotificationTestService) SomeSubscription(ctx context.Context, n, val i
 
 		select {
 		case <-notifier.Closed():
-			s.mu.Lock()
-			s.unsubscribed = true
-			s.mu.Unlock()
 		case <-subscription.Err():
-			s.mu.Lock()
-			s.unsubscribed = true
-			s.mu.Unlock()
+		}
+		if s.unsubscribed != nil {
+			s.unsubscribed <- string(subscription.ID)
 		}
 	}()
 
@@ -107,7 +96,7 @@ func (s *NotificationTestService) HangSubscription(ctx context.Context, val int)
 
 func TestNotifications(t *testing.T) {
 	server := NewServer()
-	service := &NotificationTestService{}
+	service := &NotificationTestService{unsubscribed: make(chan string)}
 
 	if err := server.RegisterName("eth", service); err != nil {
 		t.Fatalf("unable to register test service %v", err)
@@ -157,10 +146,10 @@ func TestNotifications(t *testing.T) {
 	}
 
 	clientConn.Close() // causes notification unsubscribe callback to be called
-	time.Sleep(1 * time.Second)
-
-	if !service.wasUnsubCallbackCalled() {
-		t.Error("unsubscribe callback not called after closing connection")
+	select {
+	case <-service.unsubscribed:
+	case <-time.After(1 * time.Second):
+		t.Fatal("Unsubscribe not called after one second")
 	}
 }
 
@@ -227,18 +216,19 @@ func waitForMessages(t *testing.T, in *json.Decoder, successes chan<- jsonSucces
 // for multiple different namespaces.
 func TestSubscriptionMultipleNamespaces(t *testing.T) {
 	var (
-		namespaces             = []string{"eth", "shh", "bzz"}
+		namespaces        = []string{"eth", "shh", "bzz"}
+		service           = NotificationTestService{}
+		subCount          = len(namespaces) * 2
+		notificationCount = 3
+
 		server                 = NewServer()
-		service                = NotificationTestService{}
 		clientConn, serverConn = net.Pipe()
-
-		out           = json.NewEncoder(clientConn)
-		in            = json.NewDecoder(clientConn)
-		successes     = make(chan jsonSuccessResponse)
-		failures      = make(chan jsonErrResponse)
-		notifications = make(chan jsonNotification)
-
-		errors = make(chan error, 10)
+		out                    = json.NewEncoder(clientConn)
+		in                     = json.NewDecoder(clientConn)
+		successes              = make(chan jsonSuccessResponse)
+		failures               = make(chan jsonErrResponse)
+		notifications          = make(chan jsonNotification)
+		errors                 = make(chan error, 10)
 	)
 
 	// setup and start server
@@ -255,13 +245,12 @@ func TestSubscriptionMultipleNamespaces(t *testing.T) {
 	go waitForMessages(t, in, successes, failures, notifications, errors)
 
 	// create subscriptions one by one
-	n := 3
 	for i, namespace := range namespaces {
 		request := map[string]interface{}{
 			"id":      i,
 			"method":  fmt.Sprintf("%s_subscribe", namespace),
 			"version": "2.0",
-			"params":  []interface{}{"someSubscription", n, i},
+			"params":  []interface{}{"someSubscription", notificationCount, i},
 		}
 
 		if err := out.Encode(&request); err != nil {
@@ -276,7 +265,7 @@ func TestSubscriptionMultipleNamespaces(t *testing.T) {
 			"id":      i,
 			"method":  fmt.Sprintf("%s_subscribe", namespace),
 			"version": "2.0",
-			"params":  []interface{}{"someSubscription", n, i},
+			"params":  []interface{}{"someSubscription", notificationCount, i},
 		})
 	}
 
@@ -285,46 +274,40 @@ func TestSubscriptionMultipleNamespaces(t *testing.T) {
 	}
 
 	timeout := time.After(30 * time.Second)
-	subids := make(map[string]string, 2*len(namespaces))
-	count := make(map[string]int, 2*len(namespaces))
-
-	for {
-		done := true
-		for id := range count {
-			if count, found := count[id]; !found || count < (2*n) {
+	subids := make(map[string]string, subCount)
+	count := make(map[string]int, subCount)
+	allReceived := func() bool {
+		done := len(count) == subCount
+		for _, c := range count {
+			if c < notificationCount {
 				done = false
 			}
 		}
+		return done
+	}
 
-		if done && len(count) == len(namespaces) {
-			break
-		}
-
+	for !allReceived() {
 		select {
-		case err := <-errors:
-			t.Fatal(err)
 		case suc := <-successes: // subscription created
 			subids[namespaces[int(suc.Id.(float64))]] = suc.Result.(string)
+		case notification := <-notifications:
+			count[notification.Params.Subscription]++
+		case err := <-errors:
+			t.Fatal(err)
 		case failure := <-failures:
 			t.Errorf("received error: %v", failure.Error)
-		case notification := <-notifications:
-			if cnt, found := count[notification.Params.Subscription]; found {
-				count[notification.Params.Subscription] = cnt + 1
-			} else {
-				count[notification.Params.Subscription] = 1
-			}
 		case <-timeout:
 			for _, namespace := range namespaces {
 				subid, found := subids[namespace]
 				if !found {
-					t.Errorf("Subscription for '%s' not created", namespace)
+					t.Errorf("subscription for %q not created", namespace)
 					continue
 				}
-				if count, found := count[subid]; !found || count < n {
-					t.Errorf("Didn't receive all notifications (%d<%d) in time for namespace '%s'", count, n, namespace)
+				if count, found := count[subid]; !found || count < notificationCount {
+					t.Errorf("didn't receive all notifications (%d<%d) in time for namespace %q", count, notificationCount, namespace)
 				}
 			}
-			return
+			t.Fatal("timed out")
 		}
 	}
 }