 Cleft lip and palate patients normally present with a sunken face due to collapse in the middle part of the face and inability of the upper and lower teeth to meet during chewing. This situation constitutes a serious aesthetic and mastication problem. A single surgical operation known as orthognathic surgery was traditionally performed to move the upper jaw forward to a more normal position and allow chewing function to be regained. However, due to scar tissue from the original surgical repair of the cleft palate, this procedure is known to be unstable causing bone to rapidly go back to its original position. A new concept of moving the upper jaw bone gradually by 1mm per day using a special device attached to the bone called distraction osteogenesis was established in 1996. Animal studies have shown that this technique can produce stable results with minimal relapse. The feasibility of correcting cleft deformities by gradual distraction has been confirmed by our own clinical studies. The aim of this study which is the first of its kind is to conduct a prospective randomized controlled study and compare the treatment outcomes of the current standard orthognathic surgery with distraction osteogenesis gradual bone movement. The objectives focus on four aspects: morbidity, stability, speech function and psychological impact. The results from this study will clarify several clinical dilemmas in decision making when choosing whether to use orthognathic surgery or distraction osteogenesis in the treatment of cleft lip and palate patients. In addition, it will also inform our multidisciplinary research team to improve the total care of the cleft lip and palate patients. 