Prognathic mandible affects the patient's appearance and profile. Many techniques have been advocated for the surgical correction of mandibular excess and improving aesthetic and functional results. This study was conducted to investigate the efficacy of body ostectomy for severe mandibular excess by using piezosurgery. The study consisted of nine patients. They had cosmetic and psychosocial hindrance related to mandibular excess. In the cephalometric analysis, severe mandibular excess (≥8mm reverse overjet) were selected. All patients underwent mandibular body ostectomy using piezosurgery. Clinical evaluation was made postoperatively. The average time of operation was 3.5 h with mean blood loss of around 300 ml. The postoperative course was uneventful. Generalized patient satisfactions were recorded. An acceptable occlusion was developed. The patients' facial esthetics were improved. Mandibular body ostectomy provides satisfactory outcomes (esthetic and functional) in cases of severe mandibular excess especially with intact posterior occlusion. Ultrasonic bone surgery could spare adjacent soft tissue and neurovascular bundle and hence reduce trauma, bleeding and enhance visibility. The surgical procedure duration is longer with the application of piezosurgery.