I hate answering my own questions because I don't know if it's the "correct" answer or not...but anyway. I added the mysql-connector-java-5.0.6-bin.jar to /server/default/lib and everything appears to be working now... Why can the app server find the jar/class in that directory but not find the driver if the jar was in my war/WEB-INF/lib directory? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4060903#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...