Background and aim MRI can detect intramedullary infiltration in a highly advanced manner. It is also useful for the detection of tumor extension, associated soft tissue masses, and neurological compromise. MRI can increase the rate of successful bone marrow biopsies as it can assess a large volume of bone marrow noninvasively and relatively quickly. The aim of this study was to assess the role of MRI in the evaluation of bone marrow infiltrative lesions. Patients and methods This study included 30 patients with bone marrow infiltrative lesions: 14 male and 16 female patients. The ages of the patients ranged from 8 to 75 years (mean 41.5 years). Pain was the most common symptom in the studied cases, followed by swelling. The patients in our study were examined by means of plain radiography (15 cases), computed tomography (five cases), isotopic bone scan (one case), and MRI (all cases). Results According to the pathological and radiological results, the lesions in our study were classified as follows: metastasis (12 cases); plasma cell dyscrasias (eight cases), including multiple myeloma (six cases) and plasmacytoma (two cases); lymphoma (seven cases), including non-Hodgkin’s lymphoma (five cases) and Hodgkin’s lymphoma (two cases); Ewing’s sarcoma (two cases); and leukemia (chronic lymphatic leukemia) (one case). Conclusion MRI is a sensitive method for detection of areas of marrow infiltration. The value of MRI lies in its ability to document the presence and extent of disease and to determine an appropriate radiation field.