Background: the term “anterior knee pain" is often used interchangeably with “Patellofemoral pain syndrome PFPS" or “runner's knee". PFPS can be defined as anterior knee pain involving the patella and retinaculum. Aim of the Work: to highlight the role of magnetic resonance imaging (MRI) in the diagnosis and grading of the most common causes of anterior knee pain. Patients and Methods: this study included fifty patients, their ages range between 10-60 years (average age 27 years). All presented with anterior knee pain (AKP) and were referred to the Radiology Department of El-Demerdash Hospital for MRI examination after orthopedic consultation.Results: the role of MRI in the diagnosis and grading of the most common causes of anterior knee pain have been shown in this study. These causes have been classified in to five disease categories; Patellar abnormalities represented most of them (64% of the sample size) and they included chondromalacia patella, patellar instability, transient patellar dislocation and painful bipartite patella. Hoffa's diseases represented 12% of the sample size and they included Hoffa impingement syndrome and Hoffa fibrotic bands. Patellar tendon disorders represented 6 % of the sample size and they included Patellar Tendinopathy and Osgood Schlatter Disease. Quadriceps tendon disorders represented 4% of the sample size and they included Quadriceps Tendinopathy. Other causes represented 14% of the sample size and they included torn anterior horn of the lateral meniscus and cartilage injuries. Conclusion: many factors may cause anterior knee pain. MRI is generally safe, non-ionizing, non-invasive and valuable imaging technique which has been proven to be the modality of choice for establishing an accurate diagnosis of different knee pathologies that cause anterior knee pain in different age groups. It also allows to know the extent, severity, grades and types of the lesions, what will be necessary to decide appropriate treatment. Recommendations: further studies on a larger scale of patients are needed to confirm the results obtained by this work.