Mandibular prognathism was defined that the lower jaw projecting too far forwards so that the fore teeth pass before those of upper jaw, when the mouth is shut. The dentoalveolar structures are also anteriorly displaced in a characteristic Angle's class III malocclusion. Cephalometric analysis show that the SNB angle is greater than normal. Surgery is a commonly used to treat the mandibular prognathism. Preoperative planning using cephalometric analysis and a dental model is very important for orthgnathic surgery. Orthognathic surgery almost always requires preoperative and postoperative orthodontic management in order to obtain stable postoperative occlusion and to avoid postoperative relapse, particularly in mandibular ramus osteotomy. The technique of segmental osteotomy of the anterior mandible, which is called the K le procedure, is a simple and safe procedure which is performed below the apices of the teeth and above the mental foramen. Although the Class III malocclusion can be corrected by segmental osteotomy alone, a prognathic contour remains in the lower part of the mandible. We modified the Kole procedure that we proceeded dentoalveolar osteotomy and reduction genioplasty by double horizontal osteotomy. No intermaxillary fixation is required, and no orthodontic treatment is needed. We used this procedure in 3 patients (2 females and 1 male) who can not get orthodontic management due to economic problems. This procedure can obtain a rapid aesthetic improvement.