The association of obesity and body fat distribution with hand osteoarthritis was studied in 317 Caucasian female subjects aged 40 years and above in the Baltimore Longitudinal Study of Aging. Bilateral hand radiographs taken between 1978 and 1991 were read by one investigator for grade of osteoarthritis using Kellgren-Lawrence scales. Possible risk factors, assessed at same visit as the first radiograph during this interval, included age and measures of obesity, per cent body fat, and fat distribution. Results of bivariate analyses showed that increasing grade of hand osteoarthritis was associated with increasing age, greater mean levels of waist-hip ratio and per cent body fat; there was no association with body mass index. After adjustment for age, however, none of these independent variables remained significantly associated with grade of hand osteoarthritis. These data fail to support hypotheses that measures of obesity are associated with hand osteoarthritis in women independent of their known age-related changes.