Aim: This study was carried out to investigate the effects of protractive face mask on maxillary retrusion in 2 groups of patients. Methods: Two groups, each consisting of 10 male patients, participated in the study. The first group had skeletal Class III malocclusions due to maxillary underdevelopment, while the second group had (corrected) unilateral cleft lips and palates on the left side. The subjects’ ages ranged from 5 to 8 years, and the treatment was applied with face mask for 1 year. Pre- and posttreatment lateral cephalometric films were compared. Results: The results revealed significant forward maxillary movement, which led to improvement in facial convexity in both groups, while in the Class III malocclusion group, it was more evident. There were significant changes regarding the axial inclination of the maxillary incisors, the palatal plane inclination in relation to SN, and mandibular planes. Conclusion: The crossbite in the Class III group was fully corrected and overjet was achieved after 1 year of face mask treatment, while in the cleft palate group, there was edge-to-edge relation in the incisor region, which required a second phase of orthodontic treatment. World J Orthod 2008;9:177.e29–34.