Objective: The objective of this study was to find out whether Lateral Internal Sphincterotomy (LIS) can be carried out using Local Anaesthesia (LA) hence, lowering down the cost and anaesthesia related complications in patients without compromising operative easiness or final result.Methods: One hundred patients who were diagnosed clinically as anal fissure patients and were scheduled for LIS were randomly distributed into two treatment arms. Non-probability consecutive sampling approach was employed. In the first group, LIS was carried out using LA while in the second group LIS was performed in spinal anaesthesia (SA). Age, gender, BMI, procedure time, post-operative complications like pain, post-operative nausea and vomiting (PONV), bleeding, headache, incontinence, urinary retention and patient satisfaction were the main outcome variables which were studied.Results: Out of 100 patients who were treated with LIS, 50 of these patients had SA whereas, the rests of the 50 patients were given LA. We found no statistically significant difference in the post-operative pain, PONV, bleeding, incontinence, and overall patient satisfaction but duration of surgery and post-operative complications like headache and retention of urine were considerably less in the LA group. The difference between the two groups dictated that LIS under local anaesthesia (Group A) took 13.46 minutes (SEM 0.808) lesser than Group B which was statistically significant. But the Mean postoperative pain scores of patients in both groups were not significantly different on statistical analysis nor pain scores at 12 hours from surgery and 24 hours from surgery separately i-e 'p-value>0.05'Conclusions: LIS under LA is less time-intensive, safe and has a comparable patient satisfaction rate to SA. Besides, the advantage of significant cost benefit, duration of surgery, exemption of the requirement of an anaesthetist, and less post-operative headache and PONV, LA also shows no noteworthy difference in the post-operative complications in comparison with SA.