Abstract: This study presents the development of a knowledge-based features recognition system for mechanical parts. The main aim of the research was to concentrate on recognition of rotational features, namely, blind hole, through hole and slanting hole to be used in automatic process planning system. The rule-based technique was applied to recognize rotational features. The recognition criteria were based upon geometrical data from Standard for Exchange of Product data file (STEP) of Computer-aided Design (CAD) system. The system consists of several modules, namely, pre-processing module, inference engine module and user interface module. The developed system succeeds the design activities in manufacturing industries.