Radiographic evidence of condylar atrophy was seen in 12 patients out of 206 patients who underwent surgical orthodontic treatment. All 12 patients had the same dentofacial deformity, high-angle mandibular retrognathia (Class II open bite), and all but one had bimaxillary surgery. The etiologic factors are discussed. The dentofacial deformity is considered to be the main reason for condylar resorption, but orthognathic surgery is supposed to stimulate the progress of the disease by increased loading, disk displacement, and immobilization.