Index: Lib/Cookie.py
===================================================================
--- Lib/Cookie.py	(revision 69615)
+++ Lib/Cookie.py	(working copy)
@@ -505,6 +505,8 @@
                 RA(str(self._reserved[K]))
             elif K == "httponly":
                 RA(str(self._reserved[K]))
+            elif K == "comment":
+                RA("%s=%s" % (self._reserved[K], _quote(V)))
             else:
                 RA("%s=%s" % (self._reserved[K], V))