Temporomandibular joint bony ankylosis is a debilitating condition that can cause in trismus result in poor quality of life. It can be caused by injury, infection, and systemic diseases. Current therapy and management include gap arthroplasty, interpostitionalarthroplasty, and reconstruction.We describe a case whereby we used gap arthroplasty subankylotic osteotomy method in treating bilateral bony ankylosis of TMJ. No graft was placed between the created gap space. Elastic intermaxillary fixation was placed of 4 months postoperatively to correct the occlusal relationship. At under 4-year follow up, no recurrent ankylosis was observed, the inter-incisal distance maintained at 36mm with normal occlusion Patient was very satisfied with the post-operative result.