Aim: Internal sphincterotomy is the standard surgical treatment for chronic anal fissure, but is frequently complicated by anal incontinence and The study was to evaluate the long-term outcome of anal dilatation for chronic anal fissure, especially possible negative impact on anal sphincter function. Method: The study was designed as a prospective comparative study. The study was conducted from 1 st January 2021 to 31st march 2022. A total of 584 patients diagnosed with chronic fissure in ano, fulfilling the inclusion and exclusion criteria . 584 patient underwent Sphincter‐sparing anal‐fissure surgery . Patients were followed up for 2 weeks, 1-6 months to check for any discharge, pain, bleeding, infection, and incontinence(flatus and stool). Result: 584 patients included in the study, 228 (54.7%) were female and the mean ± SD age was 36.1 ± 8.96 years (ranging from 17 to 73 years). Major complaints of patients; pain, bleeding, constipation, pruritus, perianal discharge. Recurrence occurred in 15 patients (3.6%) (12 males, three females) and eight patients (1.9%) developed incontinence (four with gas, four with soiling and seven females, one male). The complaints of all patients with gas incontinence and a patient with fluid incontinence regressed, whereas three patients had permanent fluid incontinence. Conclusions: Sphincter‐sparing anal‐fissure surgery the gold standard for the treatment of chronic anal fissure when the physicians would like to avoid recurrence and obtain the best pain relief.Given its high rate of healing and low rate of anal incontinence, fissurectomy with anoplasty is a valuable sphincter-sparing surgical treatment for chronic anal fissure.