Really, really, don't use Catalyst::Plugin::Authentication::CDBI. No, please don't. seriously. It's ancient and it doesn't integrate with any of the new authentication and session code. Authentication::Store::DBIC *can* talk to Class::DBI, and if you have a simple database and don't need to do anything complex with your queries Class::DBI will work just fine - and DBIx::Class still maintains a CDBICompat layer for people porting across to use as a springboard, so if you realise later you need the more advanced features you can do that without too much trouble too.