Traditionally, arthrocentesis involves insertion of 2 needles into the joint space of which one acts as an inflow port and the other as the outflow port. These 2 needles must triangulate and be exactly placed in the upper joint space for the procedure to be effective. Due to the difficulty in maintaining the needle position, single-puncture arthrocentesis is gaining popularity. It is relatively easier to perform and less traumatic to the joint. The authors describe a simple technique of single-puncture arthrocentesis using parts of 2 peripheral intravenous catheters of different gauges. The outflow port is formed by the catheter tube of 1 cannula while the inflow port is formed by the needle of the second cannula. Besides beings easy to perform and cost-effective, our technique provides predictable joint lavage of the joint with minimal trauma to the tissues.