diff -r 37671fc60f34 Lib/test/test_urlparse.py
--- a/Lib/test/test_urlparse.py	Thu Sep 16 17:04:49 2010 +0200
+++ b/Lib/test/test_urlparse.py	Tue Sep 28 15:42:28 2010 -0400
@@ -493,6 +493,16 @@
         self.assertEqual(urllib.parse.urlparse("x-newscheme://foo.com/stuff"),
                          ('x-newscheme', 'foo.com', '/stuff', '', '', ''))
 
+    def test_mailto_headers(self):
+        """Tests that urllib.parse.urlparse() returns headers in mailto: links
+        as query parameters.
+
+        """
+        # Issue 6640: mailto: headers should be returned as query parameters
+        eq = self.assertEqual
+        result = urllib.parse.urlparse('mailto:foo@example.com?subject=hi')
+        eq(result, ('mailto', '', 'foo@example.com', '', 'subject=hi', ''))
+
 def test_main():
     support.run_unittest(UrlParseTestCase)
 
diff -r 37671fc60f34 Lib/urllib/parse.py
--- a/Lib/urllib/parse.py	Thu Sep 16 17:04:49 2010 +0200
+++ b/Lib/urllib/parse.py	Tue Sep 28 15:42:28 2010 -0400
@@ -49,7 +49,7 @@
                'https', 'shttp', 'rtsp', 'rtspu', 'sip', 'sips',
                'mms', '', 'sftp']
 uses_query = ['http', 'wais', 'imap', 'https', 'shttp', 'mms',
-              'gopher', 'rtsp', 'rtspu', 'sip', 'sips', '']
+              'gopher', 'rtsp', 'rtspu', 'sip', 'sips', 'mailto', '']
 uses_fragment = ['ftp', 'hdl', 'http', 'gopher', 'news',
                  'nntp', 'wais', 'https', 'shttp', 'snews',
                  'file', 'prospero', '']