diff --git a/Include/object.h b/Include/object.h
index 2eb2b44..131812f 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -206,6 +206,9 @@
 	binaryfunc nb_true_divide;
 	binaryfunc nb_inplace_floor_divide;
 	binaryfunc nb_inplace_true_divide;
+
+	/* Added in release 2.5 */
+	lenfunc nb_index;
 } PyNumberMethods;
 
 typedef struct {
@@ -503,13 +506,16 @@
 /* Objects support garbage collection (see objimp.h) */
 #define Py_TPFLAGS_HAVE_GC (1L<<14)
 
-/* These two bits are preserved for Stackless Python, next after this is 16 */
+/* These two bits are preserved for Stackless Python, next after this is 17 */
 #ifdef STACKLESS
 #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION (3L<<15)
 #else
 #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION 0
 #endif
 
+/* Objects support nb_index in PyNumberMethods */
+#define Py_TPFLAGS_HAVE_INDEX (1L<<17)
+
 #define Py_TPFLAGS_DEFAULT  ( \
                              Py_TPFLAGS_HAVE_GETCHARBUFFER | \
                              Py_TPFLAGS_HAVE_SEQUENCE_IN | \
@@ -519,6 +525,7 @@
                              Py_TPFLAGS_HAVE_ITER | \
                              Py_TPFLAGS_HAVE_CLASS | \
                              Py_TPFLAGS_HAVE_STACKLESS_EXTENSION | \
+                             Py_TPFLAGS_HAVE_INDEX | \
                             0)
 
 #define PyType_HasFeature(t,f)  (((t)->tp_flags & (f)) != 0)