Background: Temporomandibular joint dysfunction (TMJD) is a clinically significant condition which can be a source of acute or chronic orofacial pain and dysfunction including limitation of mandibular movement, pain with mandibular function and joint sounds. Arthrocentesis is joint lavage which washes out these inflammatory mediators, thereby, relieving pain. Aim: The aim of this study is to evaluate the efficacy of arthrocentesis of temporomandibular joint (TMJ) followed by intra-articular injection of piroxicam in patients with TMJD. Materials and Methods: Forty TMJ's from thirty patients, aged 18-48 years (mean age 27.33 years) with clinical and radiological diagnosis of TMJD, based on clinical diagnostic criteria (CDC/TMD) were included in the study and underwent arthrocentesis followed by injection of piroxicam. Patient evaluation was done preoperatively and post operatively immediately following the procedure and on 7 th day, 2 nd , 3 rd and 4 th week, 2, 3, 4, 5 and 6 months. Pain on mouth opening on a Visual Analogue Scale (VAS) scale (score 0-10), clicking or popping sounds and maximum mouth opening were recorded at each interval. Magnetic resonance imaging (MRI) was performed before treatment and 6 months after treatment in both groups. Results: Evaluation of assisted and unassisted mouth opening showed increase at all time intervals. There was significant improvement in pain, range of motion, joint effusion and joint sounds. Conclusion: Arthrocentesis followed by intra-articular injection of piroxicam is a safe, simple, minimally invasive and effective treatment of temporomandibular joint dysfunction.