Reconversion of bone marrow is a reverse process of natural replacement of red marrow by yellow marrow. The occurrence of reconversion can be misleading and challenging in interpretation of musculoskeletal system imaging. Changes of signal intensity in bone marrow are frequently observed in radiological routine and its diversity can cause a suspicion of pathologic findings. Therefore, the knowledge about distribution of red and yellow bone marrow depending on age, concomitant diseases and presentation of the patient are essential for MR image interpretation.