This study examined the association between aerobic fitness and serum cholesterol and the effects of controlling for gender, body composition, abdominal fat, and dietary saturated fat in 262 children. The 1-mile run was used to estimate fitness. Skinfolds were used in assessing body fat. Fit children had lower total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels and higher high-density lipoprotein cholesterol levels than unfit children, except after adjustment for body fat and/or abdominal fat. Unfit children appear to be at an increased risk of unhealthy levels of serum cholesterol due primarily to increased levels of body fat.