Background and Aims: Erector spinae plane block (ESB) and Paravertebral block (PVB) are formats for post-operative analgesia. This study compares the analgesic effects of both after open cholecystectomy. Methods: fifty patients with ASA physical status I or II and ages 18 - 65 years who had open cholecystectomy surgery were randomly assigned to one of two groups: sonar guided ESB (Group 1, n = 25) or sonar guided PVB (Group 2, n = 25). After induction of general anesthesia all patients received 20 mL 0.5% bupivacaine in each technique of the study. Patients were estimated for post-operative analgesia using Visual analogue scale (VAS) at 0, 2, 4, 6, 12 and 24 h after surgery. Results: Post-operative VAS scores were lower in ESB at 4, 6, 12 and 24 h (P < 0.05). The time for first rescue analgesic requirement was significantly longer in ESB group (416 ± 68 min) than PVB group (371 ± 67 min). Regarding complications there were no significant adverse effects noted in two groups. Conclusion: Sonar-guided ESB reduced post-operative pain scores and prolonged the duration of analgesia compared to PVB after open cholecystectomy