In this pilot study, the principle of distraction osteogenesis was used to advance the midface of a boxer dog. A modified high Le Fort I-type osteotomy was performed. Following a latency period of 5 days the maxilla was distracted 14 mm in 14 consecutive days at a rate of 1 mm per day. Ten weeks after the completion of the distraction, multiple biopsies were taken across the distraction gap. Histological observation showed bone deposition in the osteotomy sites. Soft and hard tissue formation resulted in complete healing across the distraction gap. The maxillary sinus was used to accommodate the distraction device. Superimposition of the standardized lateral cephalograms taken at the end of distraction and 14 months after the removal of the distractors showed no sign of relapse in the achieved sagittal advancement of the maxilla. This small, intraoral trans-sinusal placed distractor has a completely new conceptual design, and may be helpful in distraction of maxilla in children and adults with midfacial hypoplasia.