BACKGROUND Chronic anal fissure is a common condition that causes pain and discomfort and has a significant impact on quality of life. When conservative management fails, surgical sphincterotomy can be successful. This retrospective study from a single center in Turkey included 188 patients with chronic anal fissures and aimed to compare outcomes from open and closed sphincterotomy. MATERIAL AND METHODS This retrospective study included 188 patients treated with lateral internal sphincterotomy (LIS) for chronic anal fissure between January 2015 and December 2021 in our hospital. Open LIS procedure was performed in 91 patients and closed LIS was performed in 97 patients. Demographic characteristics, postoperative complications, and recurrence were compared for these 2 methods. RESULTS Of the 188 patients included in the study, 47.9% were women and 52.1% were men. The mean age was 42.9 (20-84) years. In the open LIS group, recurrence occurred in 2 patients (2.19%), and no incontinence was observed. In the closed LIS group, recurrence occurred in 3 patients (3%; P=0.703), and incontinence developed in 5 patients (5.15%; P=0.035). CONCLUSIONS Comparing the 2 methods used in chronic anal fissure surgery, and considering the recurrence and risk of incontinence, the most feared outcome by the patient and surgeon, open LIS stands out as a superior technique, especially in young male patients.