Background Laparoscopic surgery reduces pain after donor nephrectomy; however, most patients still require a significant amount of postoperative parenteral opiate analgesia. Therefore, there is a need to investigate techniques that might further reduce postoperative pain. This study assessed the safety and efficacy of using a transversus abdominis plane (TAP) block in a randomized, double-blind, placebo-controlled trial. Methods Forty-six patients were analyzed in the trial and were randomized to undergo the TAP block procedure with either bupivacaine (n=24) or saline placebo (Control n=22) injected into the muscle plane. Prefilled syringes were dispensed with the group allocation concealed to maintain blinding. After surgery, the amount of morphine, level of pain, and measures of recovery were recorded. Results The amount of morphine used 6 hr after surgery was significantly lower in patients receiving TAP block with bupivacaine compared with the control (presented as mean [SD], 12.4 [8.4] vs. 21.2 [14.0] mg; P=0.015). However, the total amount of morphine used was similar in both groups 45.6 [31.4] vs. 52.7 [28.8] mg; P=0.771. Patients in the bupivacaine group experienced significantly less pain on postoperative days 1 (score, 19 [15] vs. 37 [20]; P=0.003) and 2 (score, 11 [10] vs. 19 [13]; P=0.031). Recovery and postoperative hospital stay were similar in both groups. There were no complications associated with the procedure. Conclusion The TAP block procedure is beneficial in reducing postoperative pain and early morphine requirements in laparoscopic live-donor nephrectomy.