diff --git a/socketio/namespace.py b/socketio/namespace.py
index c797a14..fa10cf4 100644
--- a/socketio/namespace.py
+++ b/socketio/namespace.py
@@ -54,20 +54,19 @@ class Namespace(object):
                           'close_room', 'rooms', 'disconnect'):
             setattr(self, func_name, get_wrapped_method(func_name))
 
-    def _get_handlers(self):
-        """Returns a dict of event names and handlers this namespace
-        provides."""
-        handlers = {}
+    def get_event_handler(self, event_name):
+        """Returns the event handler for requested event or ``None``."""
         for attr_name in dir(self):
             attr = getattr(self, attr_name)
             if hasattr(attr, '_event_name'):
-                event_name = getattr(attr, '_event_name')
+                _event_name = getattr(attr, '_event_name')
             elif attr_name.startswith('on_'):
-                event_name = attr_name[3:]
+                _event_name = attr_name[3:]
             else:
                 continue
-            handlers[event_name] = attr
-        return handlers
+            if _event_name == event_name:
+                return attr
+        return None
 
     @staticmethod
     def event_name(name):
diff --git a/socketio/server.py b/socketio/server.py
index 90c407c..bce6aa8 100644
--- a/socketio/server.py
+++ b/socketio/server.py
@@ -4,6 +4,7 @@ import engineio
 import six
 
 from . import base_manager
+from . import namespace as sio_namespace
 from . import packet
 
 
@@ -141,6 +142,10 @@ class Server(object):
         namespace = namespace or '/'
 
         def set_handler(handler):
+            if isinstance(self.handlers.get(namespace),
+                          sio_namespace.Namespace):
+                raise ValueError('A Namespace object has been registered '
+                                 'for this namespace.')
             if namespace not in self.handlers:
                 self.handlers[namespace] = {}
             self.handlers[namespace][event] = handler
@@ -151,8 +156,8 @@ class Server(object):
         set_handler(handler)
 
     def register_namespace(self, name, namespace_class):
-        """Register all handlers of the given ``namespace_class`` under the
-        namespace named by ``name``.
+        """Register the given ``namespace_class`` under the namespace named
+        by ``name``.
 
         :param name: The namespace's name. It can be any string.
         :param namespace_class: The sub class of ``Namespace`` to register
@@ -163,8 +168,7 @@ class Server(object):
         See documentation of ``Namespace`` class for an example.
         """
         namespace = namespace_class(name, self)
-        for event, handler in six.iteritems(namespace._get_handlers()):
-            self.on(event, handler=handler, namespace=name)
+        self.handlers[name] = namespace
         return namespace
 
     def emit(self, event, data=None, room=None, skip_sid=None, namespace=None,
@@ -441,8 +445,14 @@ class Server(object):
 
     def _trigger_event(self, event, namespace, *args):
         """Invoke an application event handler."""
-        if namespace in self.handlers and event in self.handlers[namespace]:
-            return self.handlers[namespace][event](*args)
+        handler = None
+        ns = self.handlers.get(namespace)
+        if isinstance(ns, sio_namespace.Namespace):
+            handler = ns.get_event_handler(event)
+        elif isinstance(ns, dict):
+            handler = ns.get(event)
+        if handler is not None:
+            return handler(*args)
 
     def _handle_eio_connect(self, sid, environ):
         """Handle the Engine.IO connection event."""
diff --git a/tests/test_server.py b/tests/test_server.py
index 8c10a06..1939cd5 100644
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -48,13 +48,18 @@ class TestServer(unittest.TestCase):
 
     def test_register_namespace(self, eio):
         class NS(namespace.Namespace):
-            def on_foo(self):
+            def on_foo(self, sid):
                 self.emit("bar")
+            @namespace.Namespace.event_name('foo bar')
+            def abc(self, sid):
+                self.emit("foo bar")
 
         s = server.Server()
         s.register_namespace('/ns', NS)
 
-        self.assertIsNotNone(s.handlers['/ns'].get('foo'))
+        self.assertIsNotNone(s.handlers['/ns'].get_event_handler('foo'))
+        self.assertIsNotNone(s.handlers['/ns'].get_event_handler('foo bar'))
+        self.assertIsNone(s.handlers['/ns'].get_event_handler('abc'))
 
     def test_on_bad_event_name(self, eio):
         s = server.Server()