diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 37f0a2772..f6740544c 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -419,6 +419,37 @@ class MessageHandler(BaseHandler):
             [serialize_event(c, now) for c in room_state.values()]
         )
 
+    @defer.inlineCallbacks
+    def get_joined_members(self, user_id, room_id):
+        """Get all the joined members in the room and their profile information.
+
+        If the user has left the room return the state events from when they left.
+
+        Args:
+            user_id(str): The user requesting state events.
+            room_id(str): The room ID to get all state events from.
+        Returns:
+            A dict of user_id to profile info
+        """
+        membership, membership_event_id = yield self._check_in_room_or_world_readable(
+            room_id, user_id
+        )
+
+        if membership == Membership.JOIN:
+            users_with_profile = yield self.state.get_current_user_in_room(room_id)
+        else:
+            raise NotImplementedError(
+                "Getting joined members after leaving is not implemented"
+            )
+
+        defer.returnValue({
+            user_id: {
+                "avatar_url": profile.avatar_url,
+                "display_name": profile.display_name,
+            }
+            for user_id, profile in users_with_profile.iteritems()
+        })
+
     @measure_func("_create_new_client_event")
     @defer.inlineCallbacks
     def _create_new_client_event(self, builder, requester=None, prev_event_ids=None):
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index cd388770c..4be0fee38 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -398,22 +398,19 @@ class JoinedRoomMemberListRestServlet(ClientV1RestServlet):
 
     def __init__(self, hs):
         super(JoinedRoomMemberListRestServlet, self).__init__(hs)
-        self.state = hs.get_state_handler()
+        self.message_handler = hs.get_handlers().message_handler
 
     @defer.inlineCallbacks
     def on_GET(self, request, room_id):
-        yield self.auth.get_user_by_req(request)
+        requester = yield self.auth.get_user_by_req(request)
+        user_id = requester.user.to_string()
 
-        users_with_profile = yield self.state.get_current_user_in_room(room_id)
+        users_with_profile = yield self.message_handler.get_joined_members(
+            user_id, room_id,
+        )
 
         defer.returnValue((200, {
-            "joined": {
-                user_id: {
-                    "avatar_url": profile.avatar_url,
-                    "display_name": profile.display_name,
-                }
-                for user_id, profile in users_with_profile.iteritems()
-            }
+            "joined": users_with_profile,
         }))