The association of OA with increased bone mass is controversial. This study measured BMD at the hip and spine and total body bone mineral (TBBM) by dual energy X-ray absorptiometry, and BMD at the distal forearm by single photon absorptiometry in 20 post-menopausal women with primary generalized OA. The data were compared with those from 89 normal controls. Osteoarthritic women had significantly increased BMD at the spine (P < 0.001), distal forearm (P < 0.05) and increased TBBM (P < 0.01), but no difference was seen at the femoral neck. These differences were not explained by obesity. The influence of mobility is discussed.