PURPOSE: The purpose of this study is to assess magnetic resonance (MR) imaging findings of malignant fibrous histiocytoma (MFH) of bone and to evaluate the role of contrast-enhanced MR imaging in the diagnosis of bone MFH. MATERIALS AND METHODS: MR imagings of pathologically proven bone MFH in ten patients were reviewed. Enhanced study was also performed with Gd-DTPA. The MR images were evaluated for signal intensity, homogeneity, marginal definition, presence of internal septation, cortical destruction, soft tissue extension, joint involvement and contrast enhancement. RESULTS: Tumors showed iso- or slightly high signal intensity to muscle on T1-weighted images and heterogeneously high signal intensity on T2-weighted images. Four cases showed poor-marginated borderon T2-weighted images and four cases had internal septa. Eight of nine patients with intravenous administration of Gd-DTPA showed contrast enhancement, five were heterogeneous and three were homogeneous. All cases showed cortical destruction and soft tissue extension. Five cases showed joint involvement. CONCLUSION: Bone MFH showed similar MR imaging findings of soft tissue MFH or other malignant bone tumors, but joint involvement was suggestive finding of bone MFH.