Ten patients (average age 51 years) on long-term hemodialysis (average duration 13.5 years) were examined by magnetic resonance (MR) (all cases) and CT (five cases) for cystic radiolucencies of the wrist, shoulders, and hips. MR and CT revealed more lesions of smaller size than plain films and both showed a constant communication with the joint space. Synovial hypertrophy was generally absent or very mild even in the case of large osseous erosions. The MR analysis of the content of the lesions in the wrist was quite variable: low signal on T1- and T2-weighted images (12 of 24), low signal on T1- and high signal on T2-weighted images (10 of 24), and high signal on T1- and T2-weighted images (2 of 24). The patterns of transplanted (four cases) or ungrafted (six cases) patients were indistinguishable. These results suggest an articular origin of the lesions, but different from synovial processes such as rheumatoid arthritis, and confirm their probable multifactorial pathogenesis.