Adding a flush between the merge and refresh seems to help a lot. | group = new Group(); | group.setGroupname( newGroupname() ); | orgmobDatabase.persist( group ); | // User owns the bidirectional many-to-many relationship with Group | user.getGroups().add( group ); | orgmobDatabase.merge( user ); | orgmobDatabase.flush(); | orgmobDatabase.refresh( group ); Also, after some more reading persistence type PERSIST also seems more appropriate to my needs. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3960509#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...