This study describes the use of a segmental Le Fort I osteotomy for interpositional autogenous iliac bone grafts in 5 patients with severe unilateral atrophy of the maxilla. Unilateral pterygomaxillary disjunction and osteotomy of the lateral and medial walls of the maxillary sinus were performed. The mucosa of the maxillary sinus was preserved and lifted cranially. It was stabilized with autogenous cancellous bone grafts. One side of the maxilla was gently downfractured until it replaced the original morphology of the alveolar crest. The inter-arch space was therefore reduced to the ideal level for placing implants. Lateral widening of the alveolar crest was obtained with on-lay bone grafts. Segmental osteotomy with bone grafting is a modification of Le Fort I swing osteotomy that has several advantages. The in-lay graft was not resorbed because it was rapidly revascularized and implant placement was delayed. This article presents a surgical technique for the reduction of vertical inter-arch space for the correct positioning of osseointegrated implants.