Objective: High waist circumference (WC) is associated with increased cardiovascular risk (CVR) in adulthood. However, this association is uncertain in children and adolescents yet. Methods : We performed cross-sectional analysis of data from youths aged 10-18 years who were included in the Korea National Health and Nutrition Examination Survey (2007-2014). High WC was defined as ≥90th percentile for age- and gender-specific values. We used standard cut-off values to define CVR factors including hypertension, dyslipidemia and hyperglycemia. The association between WC and CVR factors was evaluated. In order to identify when this association begins, we analyzed this relationship in different age groups; early (10-12 years)-, middle (13-15 years)- and late (16-18 years)-adolescent. Results: High WC was associated with an increased risk of having CVR factors; hypertension (odds ratio [OR]; 3.5 in boys, 1.9 in girls), high total cholesterol (OR; 3.9 in boys, 1.9 in girls), high triglyceride (OR; 4.9 in boys, 3.2 in girls), high low-density lipoprotein (LDL) cholesterol (OR; 5.0 in boys, 1.8 in girls), low high-density lipoprotein (HDL) cholesterol (OR; 2.6 in boys, 3.0 in girls) and hyperglycemia (OR; 2.8 in girls). This association between WC and CVR was shown to begin differently according to gender and CVR factor. In boys, high WC began to increase the risks of hypertension, high triglyceride and low HDL cholesterol at least from early adolescent. The association of high WC with high total cholesterol and high LDL cholesterol was shown to start from middle adolescent. There was no association between high WC and hyperglycemia. In girls, high WC started to influence the risks of high total cholesterol, high triglyceride and low HDL cholesterol at least from early adolescent. The risk of hyperglycemia began to be increased by high WC from middle adolescent. Hypertension and high LDL cholesterol began to be associated with high WC from late adolescent Conclusion: High WC in youth is associated with increased CVR. However this relation begins differently according to genders and CVR factors.