The accuracy of predicting the results of orthodontic-surgic treatment following bimaxillary anterior subapical setback osteotomy was analyzed retrospectively. Comparisons of pretreatment prediction tracings of the lateral cephalograms with the 6-month postsurgical cephalograms of 38 patients showed that there was no statistically significant difference between the actual and predicted dentoalveolar setback in both arches. The computer-generated soft tissue rpedictions were generally accurate, with the exception of the horizontal position of the lower lip, which was underestimated, and, to a lesser extent, the vertical position of the upper lip, which was also underestimated. Computerized cephalometric prediction following bimaxillary anterio subapical osteotomy is sufficiently accurate to be of value to be used routinely in treatment planning for the horizontal upper lip prediction, but some modifications are advisable to obtain a more accurate horizontal lower lip prediction.