This paper aims at supporting the knowledge engineering process by proposing an approach to map CommonKADS knowledge models into specifications based on the Production Rule Representation (PRR) language. This approach starts by proposing a metamodel of CommonKADS knowledge models. We define the concept of inference group, required to perform the mapping transformations, and an algorithm that identifies inference groups automatically. We then proceed to the definition of transformation rules. The latter are applied to map CommonKADS knowledge models into a set of PRR production rulesets, combined with UML activity diagrams.