The issue with the MDB run as tests was that there was the | <use-caller-identity/> | tag missing in the Level1CallerBean. MDB->Level1CallerBean->Level2CallerBean->Level3CallerBean If Level1CallerBean does not define an explicit run-as or use-caller-principal, the run-as defined by the MDB can never be propagated to Level2CallerBean. Level2CallerBean defines use-caller-identity. Not sure how this worked in 4.x In JBAS5, we have clear separation of run as and subject principals. More spec-like behavior. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4174705#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...