First you need to know if you can process the messages in parallel and how long the onMessage() MEthod will run. This will determine how many threads you can run in parallel (concurrency and reordering) on which queue. The MDB Pool itself is not that interesting (if enough instances are available) as the parallelity is controled by the dequeueing threads. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4205602#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...