The aim of the present morphometric investigation was to evaluate the effects of bone-anchored maxillary protraction (BAMP) in the treatment of growing patients with Class III malocclusion. The shape and size changes in the craniofacial configuration of a sample of 26 children with Class III malocclusions consecutively treated with the BAMP protocol were compared with a matched sample of 15 children with untreated Class III malocclusions. All subjects in the two groups were at a prepubertal stage of skeletal development at time of first observation. Average duration of treatment was 14 months. Significant treatment-induced modifications involved both the maxilla and the mandible. The most evident deformation consisted of marked forward displacement of the maxillary complex with more moderate favourable effects in the mandible. Deformations in the vertical dimension were not detected. The significant deformations were associated with significant differences in size in the group treated with the BAMP protocol.