diff --git a/Include/weakrefobject.h b/Include/weakrefobject.h
index daf490f..0a659b0 100644
--- a/Include/weakrefobject.h
+++ b/Include/weakrefobject.h
@@ -62,7 +62,7 @@
                                                 PyObject *callback);
 PyAPI_FUNC(PyObject *) PyWeakref_GetObject(PyObject *ref);
 
-PyAPI_FUNC(long) _PyWeakref_GetWeakrefCount(PyWeakReference *head);
+PyAPI_FUNC(Py_ssize_t) _PyWeakref_GetWeakrefCount(PyWeakReference *head);
 
 PyAPI_FUNC(void) _PyWeakref_ClearRef(PyWeakReference *self);
 
diff --git a/Misc/NEWS b/Misc/NEWS
index f2a318e..81f7ca4 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
 Core and builtins
 -----------------
 
+- _PyWeakref_GetWeakrefCount() now returns a Py_ssize_t, it previously
+  returned a long (see PEP 353).
+
 - Bug #1515471: string.replace() accepts character buffers again.
 
 - Add PyErr_WarnEx() so C code can pass the stacklevel to warnings.warn().
diff --git a/Modules/_weakref.c b/Modules/_weakref.c
index 2dfdc14..1712f12 100644
--- a/Modules/_weakref.c
+++ b/Modules/_weakref.c
@@ -17,7 +17,7 @@
     if (PyType_SUPPORTS_WEAKREFS(object->ob_type)) {
         PyWeakReference **list = GET_WEAKREFS_LISTPTR(object);
 
-        result = PyInt_FromLong(_PyWeakref_GetWeakrefCount(*list));
+        result = PyInt_FromSsize_t(_PyWeakref_GetWeakrefCount(*list));
     }
     else
         result = PyInt_FromLong(0);
@@ -37,12 +37,12 @@
 
     if (PyType_SUPPORTS_WEAKREFS(object->ob_type)) {
         PyWeakReference **list = GET_WEAKREFS_LISTPTR(object);
-        long count = _PyWeakref_GetWeakrefCount(*list);
+        Py_ssize_t count = _PyWeakref_GetWeakrefCount(*list);
 
         result = PyList_New(count);
         if (result != NULL) {
             PyWeakReference *current = *list;
-            long i;
+            Py_ssize_t i;
             for (i = 0; i < count; ++i) {
                 PyList_SET_ITEM(result, i, (PyObject *) current);
                 Py_INCREF(current);
diff --git a/Objects/weakrefobject.c b/Objects/weakrefobject.c
index bbeb3c0..826f571 100644
--- a/Objects/weakrefobject.c
+++ b/Objects/weakrefobject.c
@@ -6,10 +6,10 @@
         ((PyWeakReference **) PyObject_GET_WEAKREFS_LISTPTR(o))
 
 
-long
+Py_ssize_t
 _PyWeakref_GetWeakrefCount(PyWeakReference *head)
 {
-    long count = 0;
+    Py_ssize_t count = 0;
 
     while (head != NULL) {
         ++count;