Any chance your UserTransaction is timing out? If your point of entry (probably "onMessage") in your MDB) is starting the Tx, you can annotate it with @TransactionTimeout: http://docs.jboss.org/ejb3/embedded/api/org/jboss/annotation/ejb/Transact... ...to get fine-grained control at the method level. Otherwise, globally: http://wiki.jboss.org/wiki/Wiki.jsp?page=TransactionTimeout. Course, I don't see a Tx timeout in your stacktrace... So please post your MDB and the Message you're sending it? Where does the EM come into play in this equation? S, ALR View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4088046#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...