Corion is right, and you will be happier in the long run if you follow that advice. I just wanted to note that if I move your use Foo; / use Bar; statements after the respective BEGIN blocks, your example code works for me. I'm guessing it could also be some interaction with Exporter (but I haven't yet bothered to track it down exactly). Or, changing the calls to the functions to use the fully qualified names (Foo::...) works too.