Traditionally, process planning and scheduling for parts were carried out in a sequential way, where scheduling was done after process plans had been generated. Considering the fact that the two functions are usually complementary, it is necessary to integrate them more tightly so that performance of a manufacturing system can be improved greatly. In this paper, we present a review of the reported research in Integrated Process Planning and Scheduling (IPPS), discuss the extent of applicability of various approaches and suggest some future research trends.