Objective: To compare the analgesic efficacy of ultrasound (US) guided TAP block with landmark technique guided TAP block for management of post-op pain after open appendectomy in patients of acute appendicitis. Methods: In this study, we include 80 patients of acute appendicitis who were planned for open appendectomy were included. The study was conducted from June-2021 to Jan-2022 in Nishtar Hospital Multan. In Landmark TAP group; TAP block was given using bupivacaine (0.25%) after completion of surgical procedure using blind landmark technique. In US TAP group; TAP block was administered under US supervision. VAS Score and time of first rescue analgesia were main study outcomes. Results: Mean age was 33.5±9.9 years in landmark TAP group and 32.8±10.4 years in US TAP group (p-value 0.75). There was no significant difference in mean VAS score at 1, 6, 12 and 18 hours after surgery between the groups, However, after 24 hours of surgery mean VAS score was higher in landmark TAP group; 3.5±1.2 versus 2.9±1.0 in TAP group (p-value 0.02). Time of first rescue analgesia was significantly prolonged in US TAP group; 1320.7±275.9 minutes versus 1180.4±320.7 minutes in landmark TAP group (p-value 0.04). Conclusion: Ultrasound guided TAP block is superior to landmark guided TAP block, as it provides better analgesic outcomes in comparison of landmark guided TAP block. Keywords: Ultrasonography, landmark technique, transversus abdominus plane block.