Aerobic exercise training studies involving volunteers generally result in an improved cardiovascular risk factor profile. Little is known, however, about associations between physical activity change and risk factor change in a more representative sample, such as a community. This investigation evaluated correlations between a composite physical activity change score and change in cardiovascular risk factors from 1979 to 1985 in the cohort sample of the Stanford Five-City Project. Men (n = 380) and women (n = 427) between the ages of 18 and 74 years were evaluated for change in self-reported physical activity and change in total cholesterol, high density lipoprotein cholesterol (HDL cholesterol), systolic blood pressure, resting pulse rate, and body mass index (weight (kg)/height (m)2). For men, improvement in the composite physical activity score significantly correlated with an increase in HDL cholesterol (r = 0.14, p = 0.005) and decreases in body mass index (r = -0.16, p = 0.001) and estimated 10-year coronary heart disease risk score (r = -0.10, p = 0.056). For women, improvement in the physical activity score was associated with changes in HDL cholesterol (r = 0.11, p = 0.028) and resting pulse rate (r = -0.15, p = 0.001). These data demonstrate that an increase in physical activity over 5 years is favorably associated with changes in major cardiovascular disease risk factors in men and women and support the public health efficacy of community-wide promotion of physical activity.