Actually you can change the names to whatever you want. They just have to match in the areas I have listed below. Check your [database]-ds.xml (located in your deploy dir) and look for a tag <jndi-name>SomeName</jndi-name>. That is the name under which the datasource registers itself. That name is also used in the persistence.xml located under . <jta-data-source>java:/SomeName</jta-data-source> Just make sure the two names are the same (copy & paste it .. trust me ;) ). Or, maybe I am not getting it. Just to verify the setup: You have a [database]-ds.xml in your deploy directory and a persistance.xml in your [project]/META-INF/ dir. It is also probably also just have two *-ds.xmls in your deploy directory giving you access to the database. Just tried it and at least they both register themselves. You can even have a per-database-level in the *-ds.xml. Make sure the file name and the JNDI names are different then the first. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4137964#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...