Background: Lateral internal sphincterotomy is the only choice in the treatment of the fissure in ano. Complete and partial sphincterotomy was followed in variable individuals. But post-operative complication like incontinence, early mobilization and early recovery is to be made into account for best results among these patients.Methods: This study is made in 2015-2016 period among 52 patients with chronic fissure in ano, partial sphincterotomy i.e., division of internal sphincter below the dentate line was performed. Post-operative follows up and symptoms were recorded, in such cases treated adequately. The period of revisit was decided according to patient compliance 1 month, 3months, 6 months. The data was collected prospectively and recorded in view of change in the treatment.Results: 47 of the patients were pain free within first 5 days of surgery. Remaining 5 patients required further division for pain relief due to persistent pain after 3 weeks. The associated post-operative complication among these patients was itching due to burning sensation in and around the anus which resolved later. None among these patients developed fecal incontinence.Conclusions: Among all age group of the patients included in this study were subjected to same type of the procedure and results were recorded to give better prognosis with lowest degree of recurrence for which repeat of the same procedure gave the complete relief. Lateral internal partial sphincterotomy is an effective technique for complete relief of pain in chronic fissure in ano.