Retrospective studies into the effects of some aspects of treatment on facial development were based on x-ray films obtained in 58 men with unilateral cleft lip and palate operated on by palatal pushback. Because of mandibular retroposition, individuals subjected to systematic orthodontic treatment had better sagittal jaw relations and occlusion of incisors than insufficiently treated patients. The retroposition was attained with orthodontic proclination of upper incisors leading to a positive overjet and retraining the anterior development of the mandible. In patients with complete clefts operated on at about 6 years of age, sagittal jaw relations were more favorable than in those who had surgical repair at 4 years of age. The superior results in the group operated at a later age were due, in part, to the slighter retrusion of the maxilla. These differences were not apparent in incomplete clefts nor in patients with isolated cleft palate reported earlier. On the basis of these observations, a differentiated approach was proposed for determining the most convenient age for palatoplasty, according to individual types of clefts and their extent. The findings provided evidence of the essential role of orthodontic therapy for the configuration of the lower face in clefts.