As Peter mentioned, there have been deployment performance issues in AS-5. However, if you are using JBoss AS 5.1.0.GA then there have been many improvements. But the deployment timings don't yet match with the 4.x series of the AS. See this thread for details about EJB3 deployment performance http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4231116 As mentioned in that thread : "jaikiran" wrote : | Feel free to report any improvement or if the timing remains the same. While reporting, please provide details about your application including : | | 1) Number of EJB3 beans | 2) Approximate number of methods in each bean | 3) Time it takes to deploy this single application (its recommended that you let the server start cleanly and once its started drop your application in the deploy folder so that you get an accurate timing for the deployment). If available, the time this application used to take without this new version of EJB3. | 4) Any other information which you might feel is useful. | 5) Operating system and machine configurations While posting logs or xml content or code, please remember to wrap it in a code block by using the Code button in the message editor window. Please use the Preview button to ensure that your post is correctly formatted. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4250802#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...