Hello Raymond, Named tuples have compatibility code to enable them to work on IronPython without frame support, but unfortunately this doesn't allow pickling / unpickling of named tuples. One fix is to manually set __module__ on the named tuples once created, but I wonder if it would be possible to change the API to better support this - perhaps a default __module__ or providing an optional argument to specify it at creation time? Michael -- http://www.ironpythoninaction.com/ http://www.voidspace.org.uk/blog READ CAREFULLY. By accepting and reading this email you agree, on behalf of your employer, to release me from all obligations and waivers arising from any and all NON-NEGOTIATED agreements, licenses, terms-of-service, shrinkwrap, clickwrap, browsewrap, confidentiality, non-disclosure, non-compete and acceptable use policies (”BOGUS AGREEMENTS”) that I have entered into with your employer, its partners, licensors, agents and assigns, in perpetuity, without prejudice to my ongoing rights and privileges. You further represent that you have the authority to release me from any BOGUS AGREEMENTS on behalf of your employer.