Let me try to explain: one entry-point can be used by one thread. It means that if your session has only one entry point, than only one thread should be used for that session, unless you implement external synchronization. The "multi-thread mode" in drools is an experimental feature where Drools will spawn "internal" threads for parallel rule evaluation. Although, even when running in this mode, the external threads limit of one-per-entry-point still apply. Also, based on feedback and some problems we faced, this experimental feature will go under some critical changes over the next couple versions of Drools and so, I do not recommend it for anything other than test/research. We expect to have the definitive solution for this on Drools 6. Edson 2010/8/22 S Feseha <n_feseha(a)hotmail.com&gt; -- Edson Tirelli JBoss Drools Core Development JBoss by Red Hat @ www.jboss.com