Background: Staging and prognosis of malignant lymph nodes, as well as treatment planning, depend on the identification of mediastinal lymphadenopathy. MR images are used to distinguish between benign and malignant lymph nodes, including those of the mediastinum. Since many solid malignant and benign lesions on computed tomography (CT) appear remarkably similar, MRI provides a noninvasive way to further characterize mediastinal lesions. MRI has a greater contrast for soft tissues than CT. Objective: The present study aimed to evaluate MRI diffusion's sensitivity and specificity for differentiating between benign and malignant lesions. Determine the mean ADC for malignant mediastinal lesions especially those with mediastinal lymphadenopathy. Patients and methods:  A descriptive study included 36 patients with mediastinal lymph nodes. Patients were referred from Chest, Oncology and Cardiothoracic departments in Assiut University Hospitals for MRI assessment after being initially diagnosed by CT. The study was conducted at the Radiology Department at Assiut University Hospitals, in the period between August 2019 and April 2020. Results: ADC had 94% sensitivity and 88% specificity for   diagnosing   malignant   mediastinal   lymph nodes with overall accuracy of 92%, and area under receiver operating characteristic (ROC) curve was 0.92. Conclusion: Non-invasive diffusion-weighted MRI is highly sensitive and specific in distinction between malignant and benign mediastinal enlargement of lymph nodes. This also offers important data for grading mediastinal cancer.