Men who are more active live longer, but it is not clear if the same is true for women. We monitored 1404 women aged 50 to 74 who were free of cardiovascular disease. We assessed physical activity levels and ranked subjects into quartiles. After 16 years, 319 (23%) women had died. The relative risk of mortality, compared to the least active quartile, was as follows: second quartile, 0.95 (95% confidence interval [CI] 0.72 to 1.26); third quartile, 0.63 (95% CI 0.46 to 0.86); most active quartile, 0.67 (95% CI 0.48 to 0.92). The relative risks were not changed by adjustment for cardiac risk factors, chronic obstructive pulmonary disease, or cancer or by excluding all subjects who died in the first 6 years (to eliminate occult disease at baseline). There was no association between activity levels and cardiovascular morbidity or mortality. We conclude that women who were more active lived longer; this effect was not the result of decreased cardiovascular disease.