This study was undertaken to investigate the relationship between the depth of antegonial notch and the craniofacial morphology, and to predict the mandibular growth direction & potential class III malocclusion. The computerized analyses were carried out on longitudinal lateral cephalometric radiographs of 50 children with class III malocclusion, divided into two groups; 30 deep notch subjects (more than 2.6mm) and 20 shallow notch subjects (less than 1.5mm). The conclusions were as follows: 1. The mandibular growth direction in deep notch group was more vertically directed than in shallow notch group. 2. Deep notch group had shorter anterior & posterior cranial base than shallow notch group. 3. There was not significant difference between deep & shallow notch groups in the amount of mandibular growth during treatment period. 4. Notch depth increased in both deep & shallow notch groups during treatment period.