Background: Our aim was to investigate the relationship between metabolic syndrome (MetS) and energy-dense nutrient-poor solid snacks intakes during 3.6 y of follow-up among children and adolescents. Method: This population-based longitudinal study was conducted within the framework of the Tehran Lipid and Glucose Study, on 424 MetS free subjects, aged 6-18 y. Data on consumption of energy-dense nutrient-poor solid snacks, sweet and salty snacks, were collected at baseline (2006)(2007)(2008). Logistic regression, adjusted for age, sex, total energy intake, physical activity, dietary fiber, family history of diabetes, and body mass index, was used to assess the relationship between snacks and incident MetS. results: After adjustment for confounders, compared with the lowest quartile of total energy-dense nutrient-poor solid snacks, odds ratio of incident MetS in the highest quartile was 3.04 (95% confidence interval (CI): 1.11-8.49); for sweet snacks this was 2.88 (95% CI: 1.00-8.32), and for salty ones it was 2.85 (95% CI: 1.09-7.43). The risk of incident hypertension in the highest, compared with the lowest quartile of total and salty snacks, was 2.99 (95% CI: 1.00-8.93) and 3.35 (95% CI: 1.10-10.17), respectively. conclusion: Energy-dense nutrient-poor solid snacks, both salty and sweet, may have undesirable effects on the incidence of MetS, with salty snacks having the potential to increase risk of incident hypertension in children and adolescents as well. c hildren and adolescents with metabolic syndrome (MetS) are at increased risk of many clinical conditions in adulthood, including chronic low-grade inflammation, oxidative stress, hypertension, dyslipidemia, polycystic ovary syndrome, nonalcoholic fatty liver disease, and certain forms of cancer (1). According to the International Diabetes Federation, the global prevalence of MetS in children is increasing (2), which has been attributed mainly to nutrition transition, i.e., a shift of dietary habits from the traditional, toward a more Western way of life (3). Major changes in snacking patterns have been observed, highlighting the marked increase in the contribution of snacks to total energy and saturated fat intake, in particular among children and adolescents (4).Snacking patterns are usually identified based on the type of snack or the time when the snack was eaten (5). A recent review of current evidence on snack consumption and weight status reported data available to the controversial due to use of different definitions for snacking patterns and types of food that constituted snacks (4). According to their type, snack foods are categorized into two food groups, including energydense nutrient-poor (e.g., potato chips, chocolates, cakes, or biscuits) and low-energy high-nutrient (e.g., fruit or milk) snacks (6). Based on the snacking definition, energy-dense nutrient-poor snacks were associated with increased risk of obesity (7), whereas, in adolescents from Greece, no relationship was found between different levels of consumption and MetS and cardiovas...