The objectives of the current study, that is the first of its kind, were to determine the prevalence of the hypertriglyceridemic waist (HW) phenotype in a nationally representative sample of children, as well as the metabolic risk factors identified by HW, and to identify lifestyle habits related to this phenotype. This national survey was conducted on 4811 representative school-students. We assessed the sensitivity and specificity of the HW phenotype for abnormal anthropometric and biochemical factors by using receiver operator characteristic curves. We determined the association of dietary patterns (obtained by factor analysis), physical activity level and some environmental factors with the HW phenotype. Overall, 8.52% of participants had the HW phenotype. Those children with the HW phenotype were more likely to have cardiovascular risk factors, notably for overweight and hypercholesterolemia. The dietary pattern characterized by junk foods increased the odds of having the HW phenotype, OR=1.426 (95%CI, 1.109, 1.892), whereas the other dietary pattern including healthy foods decreased this odds, OR=0.874 (95%CI, 0.765, 0.998). The risk of the HW phenotype rose with the consumption of solid hydrogenated fat as well as white-flour bread. Low education of parents and a positive family history of diabetes mellitus, obesity and or premature cardiovascular disease were the other risk factors for the HW phenotype. Low levels of physical activity significantly increased the risk of having the HW phenotype. The HW phenotype can be used as an accurate and easy tool for screening children at metabolic risk in population-based studies.