Purpose of this prospective study was to evaluate the skeletal and dentoalveolar effects of afixed functional appliance, the Austro Repositioner, in dolicho- and brachyfacial skeletal ClassII patients. In all, 20 dolicho- and 25brachyfacial consecutive patients treated with the Austro Repositioner were compared with untreated controls (20dolicho- and 20brachyfacial patients) with the same initial dentoskeletal features. Lateral cephalograms were acquired before and 1.0±0.2year after therapy. Significant improvements in skeletal ClassII relationships were observed in both groups. The ANB angle decreased (3.56° in dolicho- and 3.13° in brachyfacial patients, P < 0.001) due to changes localized exclusively in the mandible, the SNB angle increased to 3.20° in dolicho- and 3.02° in brachyfacial patients, and the total mandibular length (Co-Pg) increased to 6.47 mm in dolicho- and 5.78 mm in brachyfacial patients (P < 0.001). Afavorable guidance of vertical pattern was also achieved in both groups, and no significant changes were observed in the upper and lower incisors in both groups. The Austro Repositioner was effective for short-term treatment of skeletal ClassII malocclusion resulting from the retrusion of the mandible in both dolicho- and brachyfacial patients.