diff -r 2150c7d6426c Doc/library/operator.rst
--- a/Doc/library/operator.rst	Sat Aug 17 01:01:23 2013 +0300
+++ b/Doc/library/operator.rst	Sat Aug 17 11:26:19 2013 +0300
@@ -109,7 +109,7 @@
 .. function:: index(a)
               __index__(a)
 
-   Return *a* converted to an integer.  Equivalent to ``a.__index__()``.
+   Return *a* converted to an integer.  Equivalent to ``type(a).__index__(a)``.
 
 
 .. function:: inv(obj)
diff -r 2150c7d6426c Lib/operator.py
--- a/Lib/operator.py	Sat Aug 17 01:01:23 2013 +0300
+++ b/Lib/operator.py	Sat Aug 17 11:26:19 2013 +0300
@@ -86,8 +86,18 @@
     return a // b
 
 def index(a):
-    "Same as a.__index__()."
-    return a.__index__()
+    "Same as type(a).__index__(a)."
+    try:
+        index = type(a).__index__
+    except AttributeError:
+        msg = ("'%s' object cannot be interpreted as an integer" %
+               type(a).__name__)
+        raise TypeError(msg)
+    n = index(a)
+    if not isinstance(n, int):
+        msg = ("__index__ returned non-int (type %s)" % type(n).__name__)
+        raise TypeError(msg)
+    return n
 
 def inv(a):
     "Same as ~a."
diff -r 2150c7d6426c Lib/test/test_operator.py
--- a/Lib/test/test_operator.py	Sat Aug 17 01:01:23 2013 +0300
+++ b/Lib/test/test_operator.py	Sat Aug 17 11:26:19 2013 +0300
@@ -170,6 +170,24 @@
         self.assertRaises(TypeError, operator.getitem, a, None)
         self.assertTrue(operator.getitem(a, 2) == 2)
 
+    def test_index(self):
+        operator = self.module
+        self.assertRaises(TypeError, operator.index)
+        self.assertRaises(TypeError, operator.index, 1, 1)
+        self.assertEqual(operator.index(42), 42)
+        self.assertRaises(TypeError, operator.index, '42')
+        self.assertRaises(TypeError, operator.index, 42.0)
+        class A:
+            def __index__(self):
+                return 42
+        a = A()
+        a.__index__ = lambda: 1729
+        self.assertEqual(operator.index(a), 42)
+        class B:
+            def __index__(self):
+                return 42.0
+        self.assertRaises(TypeError, operator.index, B())
+
     def test_indexOf(self):
         operator = self.module
         self.assertRaises(TypeError, operator.indexOf)