The purpose of this study was to evaluate the changes in condylar position following bilateral sagittal split reamus osteotomy with 5-and 10-mm setback in 10 symmetric human cadaver mandibles. A Plexiglas devise was constructed to determine the mandibular morphology and movements of the condyle and the proximal segments before and after surgery. There was no statistically significant relationship between mandibular morphology or the magnitude of setback and changes in condylar position postsurgery. All conlyles and rami tipped in a highly variable fashion in the coronal plane. In the axial plane, the lateral pole of the conlyles rotated predominantly anteriorly; the left side rotated significantly more than did the right. In the sample studied, the position of the condylar and proximal segments was altered in a highly variable and unpredictable manner, regardless of the magnitude of setback or the morphology of the mandible.