diff --git a/include/etl/message_broker.h b/include/etl/message_broker.h
index 7d000c2c..a8ce0ab5 100644
--- a/include/etl/message_broker.h
+++ b/include/etl/message_broker.h
@@ -274,11 +274,48 @@ namespace etl
     using imessage_router::accepts;
 
     //*******************************************
-    /// Message brokers accept all messages.
+    /// Message brokers accept messages determined
+    /// by the subscribed routers.
     //*******************************************
-    virtual bool accepts(etl::message_id_t) const ETL_OVERRIDE
+    virtual bool accepts(etl::message_id_t id) const ETL_OVERRIDE
     {
-      return true;
+      if (!empty())
+      {
+        // Scan the subscription lists.
+        subscription* sub = static_cast<subscription*>(head.get_next());
+
+        while (sub != ETL_NULLPTR)
+        {
+          message_id_span_t message_ids = sub->message_id_list();
+
+          message_id_span_t::iterator itr = etl::find(message_ids.begin(), message_ids.end(), id);
+
+          if (itr != message_ids.end())
+          {
+            etl::imessage_router* router = sub->get_router();
+
+            if (router->accepts(id))
+            {
+              return true;
+            }
+          }
+
+          sub = sub->next_subscription();
+        }
+      }
+
+      // Check any successor.
+      if (has_successor())
+      {
+        if (get_successor().accepts(id))
+        {
+          return true;
+        }
+      }
+
+      return false;
+
+      //return true;
     }
 
     //*******************************************
diff --git a/include/etl/message_bus.h b/include/etl/message_bus.h
index 8ed0737e..1d698e78 100644
--- a/include/etl/message_bus.h
+++ b/include/etl/message_bus.h
@@ -315,11 +315,35 @@ namespace etl
 
     //*******************************************
     /// Does this message bus accept the message id?
-    /// Yes!, it accepts everything!
+    /// Returns <b>true</b> on the first router that does.
     //*******************************************
-    bool accepts(etl::message_id_t) const ETL_OVERRIDE
+    bool accepts(etl::message_id_t id) const ETL_OVERRIDE
     {
-      return true;
+      // Check the list of subscribed routers.
+      router_list_t::iterator irouter = router_list.begin();
+
+      while (irouter != router_list.end())
+      {
+        etl::imessage_router& router = **irouter;
+
+        if (router.accepts(id))
+        {
+          return true;
+        }
+
+        ++irouter;
+      }
+
+      // Check any successor.
+      if (has_successor())
+      {
+        if (get_successor().accepts(id))
+        {
+          return true;
+        }
+      }
+
+      return false;
     }
 
     //*******************************************
diff --git a/test/test_message_broker.cpp b/test/test_message_broker.cpp
index 3a414d8e..fda9ae16 100644
--- a/test/test_message_broker.cpp
+++ b/test/test_message_broker.cpp
@@ -232,7 +232,7 @@ namespace
   SUITE(test_message_broker)
   {
     //*************************************************************************
-    TEST(message_check_broker_id)
+    TEST(test_message_check_broker_id)
     {
       Broker broker1;
       Broker broker2(2);
@@ -245,7 +245,7 @@ namespace
     }
 
     //*************************************************************************
-    TEST(message_broker_subscribe_then_unsubscribe)
+    TEST(test_message_broker_subscribe_then_unsubscribe)
     {
       Router router1(1);
       Router router2(2);
@@ -255,33 +255,27 @@ namespace
       Subscription subscription3{ router2, { Message1::ID, Message3::ID } };
 
       Broker broker; 
-      CHECK(broker.empty());
-      CHECK(broker.accepts(MESSAGE1));
-      CHECK(broker.accepts(MESSAGE2));
-      CHECK(broker.accepts(MESSAGE3));
-      CHECK(broker.accepts(MESSAGE4));
-      CHECK(broker.accepts(MESSAGE5));
-      CHECK(broker.accepts(MESSAGE6));
-
+      CHECK_TRUE(broker.empty());
+      
       broker.subscribe(subscription1);
-      CHECK(!broker.empty());
+      CHECK_FALSE(broker.empty());
 
       broker.subscribe(subscription3);
-      CHECK(!broker.empty());
+      CHECK_FALSE(broker.empty());
 
       broker.unsubscribe(router1);
-      CHECK(!broker.empty());
+      CHECK_FALSE(broker.empty());
 
       broker.unsubscribe(router2);
-      CHECK(broker.empty());
+      CHECK_TRUE(broker.empty());
 
       // There is no router3 subscription in 'broker'.
       broker.unsubscribe(router3);
-      CHECK(broker.empty());
+      CHECK_TRUE(broker.empty());
     }
 
     //*************************************************************************
-    TEST(message_broker_subscribe_then_clear)
+    TEST(test_message_broker_subscribe_then_clear)
     {
       Router router1(1);
       Router router2(2);
@@ -337,7 +331,7 @@ namespace
     }
 
     //*************************************************************************
-    TEST(message_broker_send_messages_to_broker_with_no_subscribers)
+    TEST(test_message_broker_send_messages_to_broker_with_no_subscribers)
     {
       Broker broker;
       Router router1(1);
@@ -382,7 +376,7 @@ namespace
     }
 
     //*************************************************************************
-    TEST(message_broker_send_messages_to_subscribers)
+    TEST(test_message_broker_send_messages_to_subscribers)
     {
       Broker broker;
       Router router1(1);
@@ -439,7 +433,7 @@ namespace
     }
 
     //*************************************************************************
-    TEST(message_broker_send_messages_to_specific_subscribers)
+    TEST(test_message_broker_send_messages_to_specific_subscribers)
     {
       Broker broker;
       Router router1(1);
@@ -460,7 +454,7 @@ namespace
     }
 
     //*************************************************************************
-    TEST(message_broker_send_messages_to_subscribers_after_unsubscribe)
+    TEST(test_message_broker_send_messages_to_subscribers_after_unsubscribe)
     {
       Broker broker;
       Router router1(1);
@@ -516,5 +510,53 @@ namespace
       CHECK_EQUAL(0, router2.message_unknown_count);
       CHECK_EQUAL(1, router3.message_unknown_count);
     }
+
+    //*************************************************************************
+    TEST(test_message_broker_accepts)
+    {
+      Router router1(1);
+      Router router2(2);
+      Router router3(3);
+
+      Subscription subscription1{ router1, { Message1::ID, Message3::ID } };
+      Subscription subscription2{ router2, { Message1::ID, Message2::ID, Message3::ID, Message4::ID } };
+
+      // Default constructed broker.
+      Broker broker;
+
+      CHECK_FALSE(broker.accepts(MESSAGE1));
+      CHECK_FALSE(broker.accepts(MESSAGE2));
+      CHECK_FALSE(broker.accepts(MESSAGE3));
+      CHECK_FALSE(broker.accepts(MESSAGE4));
+      CHECK_FALSE(broker.accepts(MESSAGE5));
+      CHECK_FALSE(broker.accepts(MESSAGE6));
+
+      // Subscribe router1.
+      broker.subscribe(subscription1);
+      CHECK_TRUE(broker.accepts(MESSAGE1));
+      CHECK_FALSE(broker.accepts(MESSAGE2));
+      CHECK_TRUE(broker.accepts(MESSAGE3));
+      CHECK_FALSE(broker.accepts(MESSAGE4));
+      CHECK_FALSE(broker.accepts(MESSAGE5));
+      CHECK_FALSE(broker.accepts(MESSAGE6));
+
+      // Subscribe router2.
+      broker.subscribe(subscription2);
+      CHECK_TRUE(broker.accepts(MESSAGE1));
+      CHECK_TRUE(broker.accepts(MESSAGE2));
+      CHECK_TRUE(broker.accepts(MESSAGE3));
+      CHECK_TRUE(broker.accepts(MESSAGE4));
+      CHECK_FALSE(broker.accepts(MESSAGE5));
+      CHECK_FALSE(broker.accepts(MESSAGE6));
+
+      // Set router3 as a successor.
+      broker.set_successor(router3);
+      CHECK_TRUE(broker.accepts(MESSAGE1));
+      CHECK_TRUE(broker.accepts(MESSAGE2));
+      CHECK_TRUE(broker.accepts(MESSAGE3));
+      CHECK_TRUE(broker.accepts(MESSAGE4));
+      CHECK_TRUE(broker.accepts(MESSAGE5));
+      CHECK_TRUE(broker.accepts(MESSAGE6));
+    }
   };
 }
diff --git a/test/test_message_bus.cpp b/test/test_message_bus.cpp
index 9407ee36..e7fde856 100644
--- a/test/test_message_bus.cpp
+++ b/test/test_message_bus.cpp
@@ -45,7 +45,9 @@ namespace
     MESSAGE2,
     MESSAGE3,
     MESSAGE4,
-    MESSAGE5
+    MESSAGE5,
+    MESSAGE6,
+    MESSAGE7
   };
 
   enum
@@ -105,6 +107,14 @@ namespace
 
   Response response;
 
+  struct Message6 : public etl::message<MESSAGE6>
+  {
+  };
+
+  struct Message7 : public etl::message<MESSAGE7>
+  {
+  };
+
   int call_order;
 
   //***************************************************************************
@@ -224,6 +234,27 @@ namespace
     int message_unknown_count;
   };
 
+  //***************************************************************************
+  // Router that handles message 6 and returns nothing.
+  //***************************************************************************
+  class RouterC : public etl::message_router<RouterC, Message6>
+  {
+  public:
+
+    RouterC(etl::message_router_id_t id)
+      : message_router(id)
+    {
+    }
+
+    void on_receive(const Message6&)
+    {
+    }
+
+    void on_receive_unknown(const etl::imessage&)
+    {
+    }
+  };
+
   //***************************************************************************
   template <size_t Size>
   class MessageBus : public etl::message_bus<Size>
@@ -237,7 +268,7 @@ namespace
 
     using etl::message_bus<Size>::receive;
 
-    // Hook 'receive' to count the incomimg messages.
+    // Hook 'receive' to count the incoming messages.
     void receive(etl::message_router_id_t id, const etl::imessage& msg)
     {
       ++message_count;
@@ -951,5 +982,30 @@ namespace
 
       CHECK_EQUAL(1, bus.message_count);
     }
+
+    //*************************************************************************
+    TEST(message_bus_accepts)
+    {
+      MessageBus<2> bus1;
+      MessageBus<2> bus2;
+
+      RouterA router1(ROUTER1);
+      RouterB router2(ROUTER2);
+      RouterC router3(ROUTER3);
+
+      bus1.subscribe(router1);
+      bus1.subscribe(router2);
+      bus1.set_successor(bus2);
+
+      bus2.subscribe(router3);
+
+      CHECK_TRUE(bus1.accepts(MESSAGE1));
+      CHECK_TRUE(bus1.accepts(MESSAGE2));
+      CHECK_TRUE(bus1.accepts(MESSAGE3));
+      CHECK_TRUE(bus1.accepts(MESSAGE4));
+      CHECK_TRUE(bus1.accepts(MESSAGE5));
+      CHECK_TRUE(bus1.accepts(MESSAGE6));
+      CHECK_FALSE(bus1.accepts(MESSAGE7));
+    }
   };
 }