Objectives: To compare the three non-steroidal anti-inflammatory agents (NSAIDs) diclofenac potassium, etodol - ac and naproxen sodium in relation to pain, swelling and trismus following impacted third molar surgery. Study Design: The study was a randomized and a double-blinded study which included 42 healthy young individu - als with impacted third molars and bone retention. Patients were randomly assigned to 3 groups (n: 14) to which diclofenac potassium, naproxen sodium and etodolac were administered orally an hour before the operation. Im - pacted third molars were surgically extracted with local anaesthesia. Visual analog scales (VAS) were used to assess the pain in the 6 th , 12 th hours and on the 1 st , 2 nd , 3 rd , 5 th , and 7 th days postoperatively. Swelling was evaluated using ultrasound (US) and mouth opening (trismus) was measured with a composing stick pre and post operatively on the 2 nd and 7 th days respectively. Results: Regarding pain alleviation, diclofenac potassium was better than naproxen sodium and naproxen sodium was better than etodolac but these differences were not statistically significant. US measurements showed that the swelling on postoperative 2 nd day was significantly lowest with diclofenac potassium as compared to others (p= 0.027) while naproxen sodium and etodolac acted similarly (p=0.747). No difference was noted regarding trismus in any of the groups. Conclusions: NSAIDs (diclofenac, naproxen and etodolac) are somehow similarly effective for controlling pain and trismus following extraction of mandibular third molars but diclofenac potassium surpasses others in reduc - tion of swelling