Childhood obesity is associated with unfavorable lipid profile, suggesting that obese children should be screened for hypercholesterolemia. However, the prevalence of hypercholesterolemia in childhood obesity, and the effect of the degree of obesity on lipid profile, are unknown. Eighty-nine obese children and adolescents (BMI >85%, mean age 10.4 +/- 2.5 years) and 53 non-obese control children matched for age, gender and pubertal stage participated in the study. Early morning blood samples for serum lipids were collected in all children after a 12-h fast. Mean serum cholesterol and triglycerides (TG) levels were significantly higher (p <0.05) among the obese children (cholesterol: 175.2 +/- 31.4 vs 143.3 +/- 24.3 mg/dl; TG: 122.8 +/- 69.7 vs 94.3 +/- 37.8 mg/dl in obese and control children, respectively). Among the obese children, 52% had elevated serum cholesterol levels (>170 mg/dl) compared to 16% in the controls. The degree of obesity (BMI 85-95% vs BMI >95%) had no effect on serum lipids. Unfavorable lipid levels were relatively common among obese children, suggesting that obesity should be considered a risk factor for hypercholesterolemia, and that screening obese children for hypercholesterolemia should be considered.