diff --git a/Lib/test/test_codecs.py b/Lib/test/test_codecs.py
index 8caf018..f8563f6 100644
--- a/Lib/test/test_codecs.py
+++ b/Lib/test/test_codecs.py
@@ -835,6 +835,9 @@
         self.assertEquals(encoder(u"a")[1], 1)
         self.assertEquals(encoder(u"\xe9\u0142")[1], 2)
 
+        encoder = codecs.getencoder("string-escape")
+        self.assertEquals(encoder(r'\x00')[1], 4)
+
 # From http://www.gnu.org/software/libidn/draft-josefsson-idn-test-vectors.html
 nameprep_tests = [
     # 3.1 Map to nothing.
diff --git a/Modules/_codecsmodule.c b/Modules/_codecsmodule.c
index 495e4ff..c0c8857 100644
--- a/Modules/_codecsmodule.c
+++ b/Modules/_codecsmodule.c
@@ -179,12 +179,13 @@
 	PyObject *str;
 	const char *errors = NULL;
 	char *buf;
-	Py_ssize_t len;
+	Py_ssize_t consumed, len;
 
-	if (!PyArg_ParseTuple(args, "O!|z:escape_encode",
-			      &PyString_Type, &str, &errors))
+	if (!PyArg_ParseTuple(args, "S|z:escape_encode",
+			      &str, &errors))
 		return NULL;
 
+	consumed = PyString_GET_SIZE(str);
 	str = PyString_Repr(str, 0);
 	if (!str)
 		return NULL;
@@ -196,7 +197,7 @@
 	if (_PyString_Resize(&str, len-2) < 0)
 		return NULL;
 	
-	return codec_tuple(str, PyString_Size(str));
+	return codec_tuple(str, consumed);
 }
 
 #ifdef Py_USING_UNICODE