diff -r b127046831e2 Lib/test/test_array.py
--- a/Lib/test/test_array.py	Mon Jul 23 00:24:24 2012 -0500
+++ b/Lib/test/test_array.py	Wed Jul 25 13:50:35 2012 +0200
@@ -1015,6 +1015,11 @@
         a = array.array('H', b"1234")
         self.assertEqual(len(a) * a.itemsize, 4)
 
+    def test_sizeof(self):
+        a = array.array('i', range(64))
+        buffer_size = a.buffer_info()[1] * a.itemsize
+        self.assertGreater(a.__sizeof__(), buffer_size)
+
 
 class StringTest(BaseTest):
 
diff -r b127046831e2 Modules/arraymodule.c
--- a/Modules/arraymodule.c	Mon Jul 23 00:24:24 2012 -0500
+++ b/Modules/arraymodule.c	Wed Jul 25 13:50:35 2012 +0200
@@ -1576,6 +1576,20 @@
 an array of some other type.");
 
 
+static PyObject *
+array_sizeof(PyObject *_self, PyObject *unused)
+{
+    Py_ssize_t res;
+    arrayobject *self = (arrayobject *)_self;
+    res = sizeof(arrayobject) + (self->allocated * self->ob_descr->itemsize);
+    return PyLong_FromSsize_t(res);
+}
+
+PyDoc_STRVAR(sizeof_doc,
+"__sizeof__() -> int\n\
+\n\
+Size of the array in memory, in bytes.");
+
 
 /*********************** Pickling support ************************/
 
@@ -2146,6 +2160,8 @@
      tobytes_doc},
     {"tounicode",   (PyCFunction)array_tounicode,       METH_NOARGS,
      tounicode_doc},
+    {"__sizeof__",      array_sizeof,                   METH_NOARGS,
+     sizeof_doc},
     {NULL,              NULL}           /* sentinel */
 };