Bone mineral density (BMD) of both radii and lumbar vertebrae was measured by single-photon absorptiometry and dual X-ray absorptiometry, respectively, before and 2.1-4.8 years after a unilateral wrist synovectomy in 10 patients with rheumatoid arthritis. Radial BMD on the operated side significantly increased after synovectomy, while that on the non-operated side did not change. Lumbar BMD significantly decreased after the operation. The grip strength of the operated side increased significantly after synovectomy, while there were no changes in the grip strength on the non-operated side. These findings suggest that wrist synovectomy results in pain relief and improves use, thereby increasing the BMD of the operated radius.