This works for me. If it is not working for you, please open a JIRA and attach a test case for us to reproduce and investigate. On an related note, just for the information of users reading this, it is usually better to have control facts (like Bar in your case) as the first pattern of the rule, specially in the presence of collect/accumulate. This comes from the general principle that more restrictive patterns should be written before less restrictive patterns in a rule's LHS, but what it really does is to prevent a left propagation that is usually very expensive in the presence of collect/accumulate. []s Edson 2009/4/28 techy <techluver007(a)gmail.com&gt; -- Edson Tirelli JBoss Drools Core Development JBoss, a division of Red Hat @ www.jboss.com