The use of the nasolabial flap in reconstruction of head and neck defects has proved to be efficacious and reliable. The versatility of this flap has been attributed to the fact that there is often abundant non - hair bearing skin in this well vascularized region. Also the proximity to the defect and achievement of good cosmetic result with preservation of function and least distortion of anatomy makes it the flap of choice. Therefore, these advantages of 'extended single stage nasolabial flap' in the treatment of OSMF led us to carry out this study for "Evaluation of change in mouth opening in centimeters in oral submucous fibrosis patients after surgical excision of fibrous bands along with bilateral coronoidotomy & surgical defect coverage by single stage nasolabial flap". Mouth opening in centimeters was recorded pre operatively(base line),to 1 week,2 week,3 week,4 week, 2nd month,3rd month and 6 month post operatively and the change was recorded.