to answer myself the query should have been: select p from Project as p join p.tasks as t where p.id = :projectid View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3984328#3984328 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=3984328