Objective: to determine the frequency of lingual nerve injury after the removal of impacted mandibular 3rd molar. Study Design: Cross sectional study Place and duration: outdoor patient department of Oral and Maxillofacial Surgery Hitec Dental College, Foundation College of Dentistry Peace Gernal Hospital, Nishtar Institute of Dentistry,Multan from January 2018 to January 2019 in one year duration. Results: Study included 335 patients with mean age of 20.86+ 1.95 yrs. Males were 190(56.7%) and females were 145(43.3%).lingual nerve injury was found in 28 patients(8.4%)while it was absent in 307 patients(91.6%).There was no significant effect was found on the frequency of lingual nerve injury for age or gender of the patient population. Conclusion: Lingual nerve injury is a commonly encountered complication among those undergoing extraction of impacted third molar. It should be carefully sought in all the patients undergoing the surgical procedure and improvement in surgical skills and techniques needs to be emphasized to further reduce the incidence and risk of this complication. Keywords: Impacted third molar, Lingual nerve, OPG (orthopantomogram), Dentistry, Mandible. DOI: 10.7176/JMPB/57-01 Publication date: July 31st 201