I have two rules below; the first fails to fire for all values of photo (photo is a boolean field). The second rule give the correct behavior when photo is true and false. I am new to drools and could be wrong but this feels like a bug. Can anyone give me a reason for this behavior. *BAD RULE:* # rule values at C137, header at C132 rule "Photochromatic_137" when RxOrderType(product[0].lens.material.photo == true, product[0].lens.design.lensType=="SV") then addResult("e1",results); System.out.println("Single Vision-Photo"); end *GOOD RULE (notice the - true &&):* # rule values at C137, header at C132 rule "Photochromatic_137" when RxOrderType(true && product[0].lens.material.photo == true, product[0].lens.design.lensType=="SV") then addResult("e1",results); System.out.println("Single Vision-Photo"); end Creighton Kirkendall