Aim A systematic review was carried out to analyse continence at 2 years or more after lateral internal sphincterotomy (LIS) for chronic anal fissure (CAF). Method PubMed, MEDLINE, Scopus, Embase, Ovid, SCI, Cochrane Central Register of Controlled Trials (CENTRAL) and Google Scholar were used to search the literature from 1969–2012 for studies reporting a follow‐up of more than 2 years after LIS for CAF. The primary outcome parameter analysed was continence. The secondary outcome parameters included success rate, recurrence, incidence of postoperative abscess and fistula formation and patient satisfaction. Results Of 324 studies screened, 22 (n = 4512) were included. The mean follow‐up period ranged from 24–124 months. The overall continence disturbance rate was 14% (95% CI 0.09–0.2). Weighted analysis showed flatus incontinence in 9% (95% CI 0.04–0.16), soilage/seepage in 6% (95% CI 0.03–0.1), accidental defaecation in 0.91% (95% CI 0.003–0.02), incontinence to liquid stool in 0.67% (95% CI 0.001–0.02) and incontinence to solid stool in 0.83% (95% CI 0.003–0.02) of patients. Conclusion The long‐term risk of continence disturbance after lateral internal sphincterotomy is significant. Randomized controlled trials with a long follow‐up are needed to substantiate these findings and to redefine its role in the treatment of chronic anal fissure.