Abstract Background: In latest days, medicinal cure for chronic anal fissure has replaced surgical surgery. Internal anal sphinc-ter hypertonia is an uncomfortable disorder that affects many people. This study compared the results of surgical treatment of chronic anal fissure after lateral internal sphincterotomy with manual dilatation of anus. Aim of Study: This study was aimed to contrast the out-comes of total lateral internal anal sphincterotomy and manual dilatation of anus in terms of symptoms and postoperative complications. Patients and Methods: This randomized controlled pro-spective Cohort study was conducted on 100 patients of chronic anal fissure with pain and bleeding. They were allo-cated to manual dilatation (n=50) or to lateral internal anal sphincterotomy (n=50). Results: The mean±  SD postoperative pain VAS score of MAD group is higher than LAS group after 12 hours (6.72±  0.757 vs 5.46±0.579), 24 hours (3.42±0.642 vs 2.86±0.452) and 48 hours (0.50±0.544 vs 0.46±0.542). There is a notable change in postoperative pain VAS score in between MAD and LAS groups at 12 and 24 hours (p < 0.0001). Furthermore, there is no significant change in postoperative pain VAS score between the MAD and LAS groups after 48 hours (p=0.698), Conclusion: Lateral anal sphincterotomy is better than anal dilatation in the management of chronic anal fissure in terms of early symptomatic relief, shorter hospital stay and less complication rate.