Background: Magnetic resonance imaging (MRI) has become a mainstay in the evaluation of TMJ disorders given its ability of noninvasively depicting major regional anatomic structures and demonstrating the presence of joint effusion and bone marrow signal-intensity abnormalities. Consequently, MRI has become the gold standard in diagnosing articular disc displacement Aim of the study: The aim of this work was to highlight the role of magnetic resonance imaging as the gold standard imaging modality in the assessment of Temporomandibular joint internal derangement. Patients and methods: The study was performed at radiology department in Kafr El-Sheikh general hospital after obtaining written informed consent from all patients.In this study 50 patients were enrolled from the dentistry and rheumatology departments, then were referred to radiology department. Results: The overall sensitivity of MRI examination for detecting and diagnosing TMJ internal derangement was 100%.  Conclusion: This study suggests the use of  MRI as a proper diagnostic modality for TMJ disorders due to the excellent soft tissue contrast and multiplaner capabilities that enable well demonstration of complex anatomy and well assessment of the pathological conditions of the TMJ especially internal derangement of the TMJ