Background and objectives: Effective perioperative analgesia with laparoscopic cholecystectomy enhances early recovery, ambulation, and discharge. Subcostal TAP block has been shown to reduce perioperative opioid use and provide effective perioperative analgesia.Currently,theQLB is performed as one of the perioperative pain management procedures for patients undergoing abdominal surgery. Inthe current study, we hypothesized that the analgesic efficacy of posterior QLB would be equal to or better than the subcostal TAP block in laparoscopic cholecystectomy. Methods: 106 patients were randomized for elective laparoscopic cholecystectomy. They were randomly allocated to 2 equal groups, 53 patients each. First group, patients received posterior QLB. Second group, patients received subcostal TAP block. Results: Data from 98 patients were analyzed (48 patientsin QLB group and 50 patients in the TAP group). The cumulative postoperative fentanyl consumption at 24hours in patients required postoperative opioids shows no significant difference between the two groups but with lessnumber of patients needing postoperative opioids in QLBgroup (17/48) than in the TAP group (28/50). The time to the first postoperative request for rescue analgesia was significantly longer in QLB group than in the TAP group.There was no significant difference between the two groups as regard PONV, and pain scores at 1, 6, 12, and 24 hours postoperatively. Conclusion: Posterior quadratus lumborum block can pro-vide better effective postoperative analgesia in patients undergoing laparoscopic cholecystectomy than subcostal transverses abdominis plane block does.