Background: Magnetic resonance imaging (MRI) is used more commonly in evaluation of knee trauma compared to other modalities. It is an excellent diagnostic tool that may help clinicians in the evaluation of injuries to menisci and ligaments, osseous structures, articular surfaces, and tendon, it plays an important role in clinical decision-making. Aim of the Work: The aim of the study was to determine the role of magnetic resonance imaging (MRI) in the assessment of injuries related to anterior cruciate ligament compared to arthroscopy. Patients and Methods: This study included (20) ACL injury patients referred to the Radiology Department from the Orthopedics outpatient clinic department, Al-Demerdash Hospital, Faculty of Medicine, Ain Shams University from December of 2016 to August of 2017. Results: eighteen (90%) male and 2 (10%) female patients were enrolled in this study. We found that sensitivity, specificity, PPV, NPV and accuracy were (90%, 70%, 71.4% 100%, 80 %) respectively in partial ACL injury. And the sensitivity, specificity, PPV, NPV and accuracy in complete ACL injury were (78.4%, 100%, 100%, 71.4%, 82 %) respectively. And the sensitivity, specificity, NPV, PPV and accuracy of medial meniscal tear were 99.8 %, 91.7%, 92.3%, 100%, 94% respectively and the sensitivity, specificity, NPV, PPV of lateral meniscal tear were 95.4%, 97.3%, 99%,100%, 98% respectively. Conclusion: MRI is now commonly used before diagnostic arthroscopy in most settings as an effective screening tool with most patients because it is faster, non-invasive and does not involve morbidity associated with arthroscopy. MRI findings before arthroscopy help in the management of meniscal and ligament injuries, ultimately improving patient outcome.