The records of 500 consecutive Saudi Arabian patients referred for orthodontic treatment were examined clinically and cephalometrically for Class III malocclusion. A control group was drawn at random from the same sample. The incidence of Class III was 9.4 per cent, with mandibular prognathism being the commonest presentation of the malocclusion. The upper and lower incisors exhibited a marked degree of dentoalveolar compensation, on dental bases having mean values of SNA--78.77 degrees and SNB--81.17 degrees. The maxillary length was reduced, as were the saddle and maxillary-mandibular plane angles. The gonial angle (ArGoMe), anterior and posterior facial heights, and mandibular lengths (ArGo, ArPo) were all significantly larger than the control group. The cephalometric values of the control group showed the increased tendency to bimaxillary protrusion in the Saudi Arabian sample.