The aim of this study was to assess the success of orthodontic treatment of pronounced Angle Class III malocclusions. The records of 16 patients with pretreatment mesial occlusion and negative overjet were analyzed by evaluating the plaster casts and lateral cephalograms made at the beginning (B1) and end (B2) of active treatment, which was purely orthodontic in all cases. After treatment the patients were divided into 2 groups: group 1 (n = 10) with virtually ideal occlusal relationships, and group 2 (n = 6) where this was not the case. Professional assessment of the results using the Peer Assessment Rating (PAR) Index revealed a reduction of the weighted PAR scores of 90.2% in group 1 and 68.8% in group 2. A questionnaire was specially designed to obtain information on the patient's rating of the treatment and of the treatment outcome. 75% of the patients addressed answered the questionnaire. Following correction of the frontal crossbites, both groups displayed a clear-cut improvement of the sagittal lip relationship; this sometimes had a striking effect on the facial esthetics. The size and heterogeneity of the sample permit only cautious interpretation of the results. However, the study suggests from what degree of Angle Class III malocclusion surgical intervention is more likely to be indicated, although the final decision on elective surgery of this kind must always be left to the patient. The PAR Index offers various advantages in assessing treatment results. However, in view of its lack of esthetic sensitivity, it should be supplemented by other assessment methods.