To improve the performance of forward-chaining production systems, a new parallel execution model is proposed which fires multiple rules simultaneously on multiple-processor systems. Two problems are discussed within the model, and efficient algorithms to solve these problems are proposed. The synchronization analysis algorithm determines the necessity of synchronization between rule firings, and the decomposition algorithm determines a mapping of rules on multiple-processor systems. Evaluation results on an existing production system show that a speed-up of 7. 5 is obtained by introducing the parallel firing mechanism.