This article describes the management of a 6-year-old female patient having bilateral right TMJ bony (true) ankylosis and left fibrous ankylosis having mandibular retrognathism and she was also suffering from eating, speech problems, snoring, difficulty in breathing, daytime somnolence and she is severely malnourished due to inability to eat because of nil mouth opening.. Bilateral gap arthroplasty and temporalis myofascial graft interpositioning through preauricular approach were done in surgical phase followed by the aggressive jaw physiotherapy in postsurgical period.