On Thu, May 22, 2008 11:30, Vishal Deshmukh wrote: Sure. rule "rule 1 " when condition is true then set property in some object rule "rule 2 " when property in some object has been set then action However, if you need "nested rules", you probably need to rethink the way you use rules. It would be easier to write rule 1 if condition for rule 1 is true and condition for rule 2 is true then action for rule 2. end the way the rule engine works makes this work exactly as you intended: it checks condition 1, and only if true, it checks condition 2. As a general design consideration, you want to combine as little conditions as possible. Suppose you have ten parameters, and you have all your rules test all paameters. In that case. you're better off hard coding the procedure. If you come up with the right set of rules that test only one or two of the parameters and still produce the desired behavior, then you make efficient use of the rule engine. I suggest you do some reading on how rule engines work, it helps you design better rulebases. Don't go into detail about the Rete algorithm in the Drools documentation, but rather find some more general guide. I don't know one off the top of my head, when I find one I'll post it. dagdag Christine