diff -r 7356f71fb0a4 Lib/test/test_types.py
--- a/Lib/test/test_types.py	Fri May 29 09:06:05 2015 -0400
+++ b/Lib/test/test_types.py	Fri May 29 13:04:34 2015 -0400
@@ -1206,15 +1206,9 @@
         @types.coroutine
         def foo():
             pass
-        @types.coroutine
-        def gen():
-            def _gen(): yield
-            return _gen()
-
-        for sample in (foo, gen):
-            with self.assertRaisesRegex(TypeError,
-                                        'callable wrapped .* non-coroutine'):
-                sample()
+        with self.assertRaisesRegex(TypeError,
+                                    'callable wrapped .* non-coroutine'):
+            foo()
 
     def test_duck_coro(self):
         class CoroLike:
@@ -1229,6 +1223,20 @@
             return coro
         self.assertIs(coro, foo())
 
+    def test_duck_gen(self):
+        class GenLike:
+            def send(self): pass
+            def throw(self): pass
+            def close(self): pass
+            def __iter__(self): pass
+            def __next__(self): pass
+
+        gen = GenLike()
+        @types.coroutine
+        def foo():
+            return gen
+        self.assertTrue(hasattr(foo(), '__await__'))
+
     def test_genfunc(self):
         def gen():
             yield
diff -r 7356f71fb0a4 Lib/types.py
--- a/Lib/types.py	Fri May 29 09:06:05 2015 -0400
+++ b/Lib/types.py	Fri May 29 13:04:34 2015 -0400
@@ -166,31 +166,47 @@
 
     # We don't want to import 'dis' or 'inspect' just for
     # these constants.
-    _CO_GENERATOR = 0x20
-    _CO_ITERABLE_COROUTINE = 0x100
+    CO_GENERATOR = 0x20
+    CO_ITERABLE_COROUTINE = 0x100
 
     if not callable(func):
         raise TypeError('types.coroutine() expects a callable')
 
     if (isinstance(func, FunctionType) and
         isinstance(getattr(func, '__code__', None), CodeType) and
-        (func.__code__.co_flags & _CO_GENERATOR)):
+        (func.__code__.co_flags & CO_GENERATOR)):
 
         # TODO: Implement this in C.
         co = func.__code__
         func.__code__ = CodeType(
             co.co_argcount, co.co_kwonlyargcount, co.co_nlocals,
             co.co_stacksize,
-            co.co_flags | _CO_ITERABLE_COROUTINE,
+            co.co_flags | CO_ITERABLE_COROUTINE,
             co.co_code,
             co.co_consts, co.co_names, co.co_varnames, co.co_filename,
             co.co_name, co.co_firstlineno, co.co_lnotab, co.co_freevars,
             co.co_cellvars)
         return func
 
+    # The following code is primarily to support functions that
+    # return generator-like objects (for instance generators
+    # compiled with Cython).
+
+    class GeneratorWrapper:
+        def __init__(self, gen):
+            self.__wrapped__ = gen
+            self.send = gen.send
+            self.throw = gen.throw
+            self.close = gen.close
+        def __await__(self):
+            return self.__wrapped__
+
     @_functools.wraps(func)
     def wrapped(*args, **kwargs):
         coro = func(*args, **kwargs)
+        if (coro.__class__ is GeneratorType or
+                isinstance(coro, _collections_abc.Generator)):
+            return GeneratorWrapper(coro)
         if not isinstance(coro, _collections_abc.Coroutine):
             raise TypeError(
                 'callable wrapped with types.coroutine() returned '