Abstract Objective The effect of physical activity on musculoskeletal health in older adults is not completely understood. The aim of this study was to determine the relationship between physical activity and 5-year changes in physical performance tests and bone mineral density (BMD) in postmenopausal women. Study design The design was a 5-year cohort study. Main outcome measures Subjects were 507 women (55–74 years old) living in a rural community in Japan. Physical activity assessed included housework, farm work, and moderate leisure-time physical activity within the previous week. Measurements at baseline included handgrip strength, walking time (timed “Up & Go” test) and BMD of the femoral neck and vertebrae. Five-year changes in these measures (outcome variables) were compared among groups with different levels of physical activity by analysis of covariance. Results Women who did not do housework performed worse in changes in handgrip strength (difference=2.22kg, P=0.0201) and worse in changes in the walking time (difference=0.54s, P=0.0072) than those who did housework alone. Women who spent at least 9h per week (median=24) doing farm work performed better in changes in handgrip strength (difference=0.28kg, P=0.0334), but worse in changes in the walking time (difference=0.66s, P<0.0001) than those who did not do farm work. However, leisure-time activity was not associated with changes in any outcome variable, and none of the physical activities predicted BMD changes. Conclusions Engaging in housework and farm work are determinants of physical function in postmenopausal women, which may help them maintain independence in daily living.