msg_display_format="%d/%m/%Y - %H:%M:%S" This works: <dtml-var "mysqtime2zopetime_py('20010216172030').strftime(msg_display_format)"> ==> 16/02/2001 - 17:20:30 This works: <dtml-var "mysqtime2zopetime_py('20010216172030')" fmt="%d/%m/%Y - %H:%M:%S"> ==> 16/02/2001 - 17:20:30 This does NOT work: <dtml-var "mysqtime2zopetime_py('20010216172030')" fmt=msg_display_format> I solved my problems by switching from fmt() to strftime(). Perhaps that helps other people. But what if I can't use strftime() and have to rely on fmt()? Peter