Purpose : The purpose of this study is to assess magnetic resonance (MR) imaging findings of malignant fibroushistiocytoma (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. Enhancedstudy was also performed with Gd-DTPA. The MR images were evaluated for signal intensity, homogeneity, marginaldefinition, presence of internal septation, cortical destruction, soft tissue extension, joint involvement andcontrast enhancement. Results : Tumors showed iso- or slightly high signal intensity to muscle on T1-weightedimages 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 ofGd-DTPA showed contrast enhancement, five were heterogeneous and three were homogeneous. All cases showed corticaldestruction and soft tissue extension. Five cases showed joint involvement. Conclusion : Bone MFH showed similarMR imaging findings of soft tissue MFH or other malignant bone tumors, but joint involvement was suggestivefinding of bone MFH.