Despite lifestyle management, children with high-risk hyperlipidemias may become overweight, and this may further adversely impact their lipid profile. Regression analysis was used to determine changes over time in adiposity and their association with lipid profiles and other risk factors for hyperlipidemic children followed in a lipid disorder clinic. 184 patients were included. Median age at presentation was 7 years (2-17 years), and median duration of follow-up was 9 years (5-20 years). Mean initial total cholesterol was 6.9+/-1.6 mmol/L, low-density lipoproteins were 5.2+/-1.7 mmol/L, high-density lipoproteins were 1.2 +/- 0.4 mmol/L, triglycerides were 1.1+/-0.8 mmol/L, and body mass index z score was +0.4+/-1.0. A significant increase in body mass index z score (+0.032/year, P< .001) was observed. There was an associated significant increase in total cholesterol and triglyceride levels and decrease in high-density lipoprotein levels over time. Worsening adiposity is prevalent in hyperlipidemic children and adversely affects their lipid profiles and cardiovascular risk.