In edentulous patients with a prognathic mandible, a pronounced chin and extensive resorption of the lower alveolar ridge, the commonly used techniques of ramus osteotomy and chin reduction will not give optimal results in the majority of cases. The solution of this problem can be obtained by mandibular body ostectomy and a sagittal rotation of the frontal part of the lower jaw. By this operation the originally horizontally orientated upper plane of the chin area is placed in a more vertical position. This operative technique gives a better predictable facial contour than the conventional methods. It causes no unfavorable displacement of the lower lip and, which is very important, it gives an absolute increase of height of the lower alveolar ridge and a more favorable inclination of the frontal part of the alveolar process from a prosthetic point of view. The problems encountered and the results obtained by this technique will be demonstrated by a short case presentation.