This paper reports a system which employs string based syntactic pattern recognition techniques for feature extraction. A B-rep based solid model of the component is used for processing the face boundaries (loops) to derive boundary strings which are syntactically analysed to detect feature signatures. The detected signatures are geometrically verified, and the positional and dimensional parameters of the features are calculated. The system is capable of detecting features with complex cross sections; compound features which include nested and intersecting features; and various types of holes and pockets. These capabilities of the system make it an effective interface between a geometric solid modeller and various application programs.