Aim: The orthodontic treatment of an adolescent female patient with Class I malocclusion, extremely deep anterior overbite, and congenital absence of three mandibular teeth is described. Methods: Autotransplantation of two developing premolars from the maxilla to the mandibular posterior region was an important part of the treatment plan. Using a segmented approach, and a treatment period of 1 year and 10 months, a satisfactory result was obtained, both sagittally and vertically. Since it was possible to keep an optimal mandibular incisor inclination and position, the posttreatment facial profile is excellent. Conclusion: The autotransplantation of two developing premolars, which was fundamental for the achievement of this biologic treatment solution, is an exciting technique. World J Orthod 2001;2:45–50.