Common carotid intima-media thickness was measured by B-mode ultrasound imaging in 46 children (mean age, 7.4 years) with serum cholesterol > or = 6.4 mmol/L (mean, 8.25 mmol/L) and in 48 children (mean age, 6.4 years) with serum cholesterol < 6.4 mmol/L (mean, 4.60 mmol/L). Maximum thickness was significantly higher in hypercholesterolemic children than in control children (0.50 versus 0.47 mm, P = .007). Subgroup analysis showed that only in children > 6.2 years old (the median of all the children's ages) was maximum thickness significantly higher in hypercholesterolemic children than in control children (0.51 versus 0.48 mm, P = .014). The odds ratio (OR) of common carotid intima-media thickening (maximum thickness of the far wall higher than the 95th percentile of the control group, 0.51 mm) between patients and control subjects was statistically significant both in univariate analysis (OR, 6.39; 95% confidence interval, 1.19 to 32.3; P = .025) and after age (OR, 5.96; 95% confidence interval, 1.09 to 32.4; P = .039) and sex (OR, 7.54; 95% confidence interval, 1.38 to 41.2; P = .020) were controlled for. Children > 6 years old with serum cholesterol > or = 6.4 mmol/L show increased thickness of the common carotid intima-media.