diff -r c8adc2c13c8b Lib/asyncio/locks.py
--- a/Lib/asyncio/locks.py	Wed May 13 10:58:35 2015 -0500
+++ b/Lib/asyncio/locks.py	Wed May 13 12:27:25 2015 -0400
@@ -3,12 +3,16 @@
 __all__ = ['Lock', 'Event', 'Condition', 'Semaphore', 'BoundedSemaphore']
 
 import collections
+import sys
 
 from . import events
 from . import futures
 from .coroutines import coroutine
 
 
+_PY35 = sys.version_info >= (3, 5)
+
+
 class _ContextManager:
     """Context manager.
 
@@ -179,6 +183,16 @@
         yield from self.acquire()
         return _ContextManager(self)
 
+    if _PY35:
+        @coroutine
+        def __aenter__(self):
+            yield from self.acquire()
+            return self
+
+        @coroutine
+        def __aexit__(self, exc_type, exc, tb):
+            self.release()
+
 
 class Event:
     """Asynchronous equivalent to threading.Event.
@@ -369,6 +383,16 @@
         yield from self.acquire()
         return _ContextManager(self)
 
+    if _PY35:
+        @coroutine
+        def __aenter__(self):
+            yield from self.acquire()
+            return self
+
+        @coroutine
+        def __aexit__(self, exc_type, exc, tb):
+            self.release()
+
 
 class Semaphore:
     """A Semaphore implementation.
@@ -454,6 +478,16 @@
         yield from self.acquire()
         return _ContextManager(self)
 
+    if _PY35:
+        @coroutine
+        def __aenter__(self):
+            yield from self.acquire()
+            return self
+
+        @coroutine
+        def __aexit__(self, exc_type, exc, tb):
+            self.release()
+
 
 class BoundedSemaphore(Semaphore):
     """A bounded semaphore implementation.
diff -r c8adc2c13c8b Lib/test/test_asyncio/test_pep492.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Lib/test/test_asyncio/test_pep492.py	Wed May 13 12:27:25 2015 -0400
@@ -0,0 +1,46 @@
+"""Tests support for new syntax introduced by PEP 492."""
+
+import unittest
+from unittest import mock
+
+import asyncio
+from asyncio import test_utils
+
+
+class BaseTest(test_utils.TestCase):
+
+    def setUp(self):
+        self.loop = asyncio.BaseEventLoop()
+        self.loop._process_events = mock.Mock()
+        self.loop._selector = mock.Mock()
+        self.loop._selector.select.return_value = ()
+        self.set_event_loop(self.loop)
+
+
+class LockTests(BaseTest):
+
+    def test_context_manager(self):
+        primitives = [
+            asyncio.Lock(loop=self.loop),
+            asyncio.Condition(loop=self.loop),
+            asyncio.Semaphore(loop=self.loop),
+            asyncio.BoundedSemaphore(loop=self.loop),
+        ]
+
+        async def test(lock):
+            await asyncio.sleep(0.01, loop=self.loop)
+            self.assertFalse(lock.locked())
+            async with lock as _lock:
+                self.assertIs(lock, _lock)
+                self.assertTrue(lock.locked())
+                await asyncio.sleep(0.01, loop=self.loop)
+                self.assertTrue(lock.locked())
+            self.assertFalse(lock.locked())
+
+        for primitive in primitives:
+            self.loop.run_until_complete(test(primitive))
+            self.assertFalse(primitive.locked())
+
+
+if __name__ == '__main__':
+    unittest.main()