Objective: To ascertain the prevalence and sociodemographic correlates of cardiometabolic risk factors in adults and school-aged children from Mesoamerica. Design: Cross-sectional study with convenience sampling. In adults, metabolic syndrome was defined according to the National Cholesterol Education Program's Adult Treatment Panel III (ATP III) criteria. In children, we calculated a continuous sex-and age-standardized metabolic risk score using variables corresponding to adult ATP III criteria. Metabolic syndrome prevalence in adults and risk score distribution in children were compared across levels of sociodemographic characteristics with use of Poisson and linear regression, respectively. Setting: Capital cities of Guatemala, El Salvador, the Dominican Republic, Honduras, Nicaragua, Panama, Costa Rica, the Mexican State of Chiapas (Tuxtla Gutiérrez city) and Belize. Subjects: Families (n 267), comprising one child aged 7-12 years and their biological parents. Results: The prevalence of metabolic syndrome was 37·9 % among women and 35·3 % among men. The most common component was low HDL cholesterol, 83·3 % in women and 78·9 % in men. Prevalence was positively associated with age. In women, metabolic syndrome was inversely related to education level whereas in men it was positively associated with household food security and height, after adjustment. The metabolic risk score in children was inversely related to parental height, and positively associated with height-for-age and with having parents with the metabolic syndrome. Conclusions: Metabolic syndrome is highly prevalent in Mesoamerica. The burden of metabolic risk factors disproportionately affects women and children of lower socio-economic status and men of higher socio-economic status.