Background: The anterior iliac crest is the most common site used for harvesting autologous bone graft. This can lead to acute and chronic iliac crest donor site pain leading to significant morbidity. Quadratus lumborum block is a newer advanced block which may help to alleviate this pain. This study aims to evaluate the effect of quadratus lumborum block on post operative analgesia in iliac crest bone graft patients. Subjects and Methods: A total of 60 patients aged between 18 yrs to 65 yrs were randomised into two equal groups. Group A received wound infiltration with local anesthesia. Group B received ultrasound guided quadratus lumborum block. Pain scores and opioid consumption were recorded in both groups. Results: Demographic profile was comparable in both the groups. The VAS score was significantly less in group B when compared to group A at 4th, 8th and 12th hrs (p <0.0001). The opioid consumption was 250.28±40.65 in group A and 100.57±25.48 group B. Conclusion: Ultrasound guided Quadratus lumborum block effectively reduces post operative pain in anterior iliac crest bone graft site when compared to local anesthetic wound infiltration.