Abstract The position of the mandibular condyle in patients treated for mandibular protrusion by the oblique vertical osteotomy of the mandibular rami was studied on temporomandibular joint radiographs exposed according to the oblique transcranial projection. Forty-four adults participated in the study, and the radiographs were taken before the operation, 6 weeks postoperatively and 1 year postoperatively. At the 6-week postoperative control all the variables measured indicated a significant downward and forward displacement of the condylar fragment of ahout 1 mm. The changes did not increase the variability of the joint morphology. At the 1-year postoperative control there were still significant differences in the position of the condyle compared with the pretreatment recording. A slight tendency to normalization was, however, observed. The mobility of the condyle, which was greatly restricted at the 6-week postoperative control, was fully restituted 1 year after the operation.