20 children with hemophilia were examined with Magnetic Resonance Imaging (MRI) to determine if MRI could be used to assess hemophilic arthropathy, especially in the early stages. 28 joints of the appendicular skeleton were imaged, including 17 knees, 10 ankles and 1 elbow. The results were compared to clinical and plain radiographic assessments and to the surgical findings when synovectomy was performed. MRI is able to evaluate the components of hemophilic arthropathy such as fluid effussion, synovial hypertrophy, the status of the articular cartilage, and bony lesions. These lesions can be discovered at an early stage when plain radiographs are still normal. MRI seems to be useful for the selection of patients needing early treatment of hemophilic arthropathy and in monitoring response to therapy.