diff -r c5186045395e Lib/asyncio/base_events.py
--- a/Lib/asyncio/base_events.py	Wed Jun 04 00:42:04 2014 +0200
+++ b/Lib/asyncio/base_events.py	Wed Jun 04 01:38:49 2014 +0200
@@ -119,6 +119,7 @@ class Server(events.AbstractServer):
 class BaseEventLoop(events.AbstractEventLoop):
 
     def __init__(self):
+        self._closed = False
         self._ready = collections.deque()
         self._scheduled = []
         self._default_executor = None
@@ -128,6 +129,11 @@ class BaseEventLoop(events.AbstractEvent
         self._exception_handler = None
         self._debug = False
 
+    def __repr__(self):
+        return ('<%s running=%s closed=%s debug=%s>'
+                % (self.__class__.__name__, self.is_running(),
+                   self._closed, self.get_debug()))
+
     def _make_socket_transport(self, sock, protocol, waiter=None, *,
                                extra=None, server=None):
         """Create socket transport."""
@@ -173,8 +179,13 @@ class BaseEventLoop(events.AbstractEvent
         """Process selector events."""
         raise NotImplementedError
 
+    def _check_closed(self):
+        if self._closed:
+            raise RuntimeError('Event loop is closed')
+
     def run_forever(self):
         """Run until stop() is called."""
+        self._check_closed()
         if self._running:
             raise RuntimeError('Event loop is running.')
         self._running = True
@@ -198,6 +209,7 @@ class BaseEventLoop(events.AbstractEvent
 
         Return the Future's result, or raise its exception.
         """
+        self._check_closed()
         future = tasks.async(future, loop=self)
         future.add_done_callback(_raise_stop_error)
         self.run_forever()
@@ -222,6 +234,9 @@ class BaseEventLoop(events.AbstractEvent
         This clears the queues and shuts down the executor,
         but does not wait for the executor to finish.
         """
+        if self._closed:
+            return
+        self._closed = True
         self._ready.clear()
         self._scheduled.clear()
         executor = self._default_executor
diff -r c5186045395e Lib/asyncio/proactor_events.py
--- a/Lib/asyncio/proactor_events.py	Wed Jun 04 00:42:04 2014 +0200
+++ b/Lib/asyncio/proactor_events.py	Wed Jun 04 01:38:49 2014 +0200
@@ -354,12 +354,12 @@ class BaseProactorEventLoop(base_events.
 
     def close(self):
         if self._proactor is not None:
+            self._stop_accept_futures()
             self._close_self_pipe()
             self._proactor.close()
             self._proactor = None
             self._selector = None
             super().close()
-        self._accept_futures.clear()
 
     def sock_recv(self, sock, n):
         return self._proactor.recv(sock, n)
@@ -428,6 +428,9 @@ class BaseProactorEventLoop(base_events.
                     self._make_socket_transport(
                         conn, protocol,
                         extra={'peername': addr}, server=server)
+                if self._proactor is None:
+                    # the event loop was closed
+                    return
                 f = self._proactor.accept(sock)
             except OSError as exc:
                 if sock.fileno() != -1:
@@ -448,8 +451,12 @@ class BaseProactorEventLoop(base_events.
     def _process_events(self, event_list):
         pass    # XXX hard work currently done in poll
 
-    def _stop_serving(self, sock):
+    def _stop_accept_futures(self):
         for future in self._accept_futures.values():
             future.cancel()
+        self._accept_futures.clear()
+
+    def _stop_serving(self, sock):
+        self._stop_accept_futures()
         self._proactor._stop_serving(sock)
         sock.close()
diff -r c5186045395e Lib/test/test_asyncio/test_base_events.py
--- a/Lib/test/test_asyncio/test_base_events.py	Wed Jun 04 00:42:04 2014 +0200
+++ b/Lib/test/test_asyncio/test_base_events.py	Wed Jun 04 01:38:49 2014 +0200
@@ -52,6 +52,20 @@ class BaseEventLoopTests(unittest.TestCa
         gen = self.loop._make_subprocess_transport(m, m, m, m, m, m, m)
         self.assertRaises(NotImplementedError, next, iter(gen))
 
+    def test_close(self):
+        self.assertFalse(self.loop._closed)
+        self.loop.close()
+        self.assertTrue(self.loop._closed)
+
+        # it should be possible to call close() more than once
+        self.loop.close()
+        self.loop.close()
+
+        # operation blocked when the loop is closed
+        f = asyncio.Future(loop=self.loop)
+        self.assertRaises(RuntimeError, self.loop.run_forever)
+        self.assertRaises(RuntimeError, self.loop.run_until_complete, f)
+
     def test__add_callback_handle(self):
         h = asyncio.Handle(lambda: False, (), self.loop)
 
diff -r c5186045395e Lib/test/test_asyncio/test_selector_events.py
--- a/Lib/test/test_asyncio/test_selector_events.py	Wed Jun 04 00:42:04 2014 +0200
+++ b/Lib/test/test_asyncio/test_selector_events.py	Wed Jun 04 01:38:49 2014 +0200
@@ -80,6 +80,7 @@ class BaseSelectorEventLoopTests(unittes
 
         self.loop._selector.close()
         self.loop._selector = selector = mock.Mock()
+
         self.loop.close()
         self.assertIsNone(self.loop._selector)
         self.assertIsNone(self.loop._csock)
@@ -89,9 +90,20 @@ class BaseSelectorEventLoopTests(unittes
         csock.close.assert_called_with()
         remove_reader.assert_called_with(7)
 
+        # it should be possible to call close() more than once
         self.loop.close()
         self.loop.close()
 
+        # operation blocked when the loop is closed
+        f = asyncio.Future(loop=self.loop)
+        self.assertRaises(RuntimeError, self.loop.run_forever)
+        self.assertRaises(RuntimeError, self.loop.run_until_complete, f)
+        fd = 0
+        def callback():
+            pass
+        self.assertRaises(RuntimeError, self.loop.add_reader, fd, callback)
+        self.assertRaises(RuntimeError, self.loop.add_writer, fd, callback)
+
     def test_close_no_selector(self):
         ssock = self.loop._ssock
         csock = self.loop._csock