diff -r e057a7d18fa2 Lib/test/test_array.py
--- a/Lib/test/test_array.py	Mon Aug 06 16:09:09 2012 -0400
+++ b/Lib/test/test_array.py	Fri Aug 10 14:21:27 2012 +0200
@@ -788,6 +788,19 @@
             warnings.filterwarnings("ignore", '', DeprecationWarning)
             ArraySubclassWithKwargs('b', newarg=1)
 
+    @test_support.cpython_only
+    def test_sizeof_with_buffer(self):
+        a = array.array(self.typecode, self.example)
+        basesize = test_support.calcvobjsize('4P')
+        buffer_size = a.buffer_info()[1] * a.itemsize
+        test_support.check_sizeof(self, a, basesize + buffer_size)
+
+    @test_support.cpython_only
+    def test_sizeof_without_buffer(self):
+        a = array.array(self.typecode)
+        basesize = test_support.calcvobjsize('4P')
+        test_support.check_sizeof(self, a, basesize)
+
 
 class StringTest(BaseTest):
 
diff -r e057a7d18fa2 Modules/arraymodule.c
--- a/Modules/arraymodule.c	Mon Aug 06 16:09:09 2012 -0400
+++ b/Modules/arraymodule.c	Fri Aug 10 14:21:27 2012 +0200
@@ -1477,6 +1477,19 @@
 is raised.  Use array.fromstring(ustr.decode(...)) to\n\
 append Unicode data to an array of some other type.");
 
+static PyObject *
+array_sizeof(arrayobject *self, PyObject *unused)
+{
+    Py_ssize_t res;
+    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.");
+
 
 static PyObject *
 array_tounicode(arrayobject *self, PyObject *unused)
@@ -1606,6 +1619,8 @@
 #endif
     {"write",           (PyCFunction)array_tofile_as_write,     METH_O,
      tofile_doc},
+    {"__sizeof__",      (PyCFunction)array_sizeof,      METH_NOARGS,
+     sizeof_doc},
     {NULL,              NULL}           /* sentinel */
 };