Background: Surgical extraction of mandibular third molar teeth is a commonly performed treatment in oral and maxillofacial surgery departments. The present study was conducted to assess efficacy of platelet rich plasma (PRP) on mouth opening and pain after surgical extraction of mandibular third molars. Materials & Methods: 80 patients with impacted mandibular wisdom teeth of both genders were divided into 2 groups of 40 each. Group I patients were given PRP and group II was control group (Non- PRP). The pain score and trismus was measured using Vernier caliper. Results: The mean pain score (VAS) before the surgery was 3.2 and 4.1, immediately after surgery was 2.8 and 4.0, pain (3rd day) was 1.7 and 3.4 and pain (7th day) was 1.1 and 2.6 in group I and II respectively. The difference was significant (P< 0.05). Trismus was present in 6 in group I and 15 in group II. The difference was significant (P< 0.05). Conclusion: Leukocyte-rich platelet rich plasma (PRP) has the potential to accelerate the healing process, and it can also reduce discomfort and trismus (the involuntary opening of the mouth) following surgical removal of mandibular third molar teeth.