The anterior cruciate ligament (ACL) tear is one of the most common knee injuries. Aim; to evaluate the effect of duration for injury on IKDC score with an anterior cruciate ligament injury patients. Patients and methods; Non-equivalent control group design was utilized to conduct this study. The study sample,60 adult patients with an ACL injury, patients were divided into two equal groups, group one their injury less than 3 months and group two their duration of injury more than 3 months. Tools; the International Knee Documentation Committee (IKDC) scale and exercise program. Results, the mean age were (24.7), and the majority of them were students, regarding the IKDC scale there was a highly statistically significant difference between both groups during pre-operative and all of the follow up periods. Conclusion; An improvement was observed at 3&6 months follow up of patients with an ACL injury of less than 3 months than those patients whose injury more than 3 months. Recommendation; providing patients with instructions for seeking medical advice for their sports injuries of great importance for early diagnosis and management of their injuries.