Mediastinal lipomatosis induced by steroid is an unusual byproduct of such theraphy and has been reportedafter prolonged and large doses of steroid therapy. The radiologic findings of mediastinal lipomatosis in simplechest film are nonspecific, but with the advent of CT scan, differentiation the fatty lesion from othermediastinal diseases can be made easily. Recently we expended steroid induced huge mediastinal lipomatosis andreport the case with review including radiologic findings.