Introduction: An anterior cruciate ligament (ACL) is the most commonly injured ligament in sports persons. ACL reconstruction is a common ligament reconstruction to restore functional knee stability. we conducted the present study to evaluate the functional outcomes in arthroscopic anterior cruciate ligament (ACL) reconstruction using peroneus longus in persons presenting to PGIMS, Rohtak. Material & method : A prospective Study of 27 patients of aged 15-45 years having MRI proven anterior cruciate ligament injury was conducted at Department of Orthopaedics, Pt. B.D. Sharma PGIMS, Rohtak (Haryana) from April, 2021 to May, 2022 after ethical clearance. Exclusion criteria included Patient refusal, Patients less than 15 years of age, Patients having any other pathological disease like osteoarthritis, Patients with any psychiatric disorder, Revision ACL Surgery and Multi ligament knee injury. Final outcome was assessed as per Tegner Activity Scale, Lysholm score, IKDC, subjective score,AOFAS Score. Follow-up done at 0 week, 3 week, 3 month and 6 month. Result: The mean age at the time of surgery was 27.73 ± 7.06 years. Maximum number of patients were observed to be lying in the second decade of life as per this study. Male preponderance was found in the present study. The total Tegner score improved significantly from a mean and SD of 1.37 (0.85) at 0 week to 7.33 (1.06), the total Lysholm score improved significantly from a mean and SD of 33.70 (11.72) at 0 week to 88.70 (8.57) postoperatively, total IKDC improved significantly from a mean and SD of 29.27 (2.18) at 0 week to 42.23 (2.26) postoperatively and total AOFAS improved from a mean and SD of 18.70 (11.46) at 0 week to 121.33 (17.27) postoperatively. On pair wise comparison for individual scores using Wilcoxon paired t test, significant differences were seen among pairs of interval of time except between at 3 months and at 6 months. Keywords: ACL, Arthroscopy, Peroneus, Autograft