This study explored the association of physical activity with body fatness and abdominal obesity in 1,004 premenopausal white women who participated in the Third National Health and Nutrition Examination Survey. Physical activity was classified into four levels based on fitness criteria from the American College of Sports Medicine. Standard protocols were used for measuring body mass index (BMI), percent body fat, and waist-to-hip ratio (WHR). Means for BMI, percent body fat, and WHR were calculated for each physical activity level. Analysis of variance procedures were performed, followed by pair-wise comparisons, to determine differences among means and for trends. Mean BMI, percent body fat, and WHR were significantly less ( P < .001) at each higher physical activity level except between Levels 0 and 1. The ability of increased daily physical activity to minimize age-related increases in abdominal obesity could be a strong incentive for women approaching menopause to become more physically active.