ABSTRACT: Exposure to environmental chemicals during developmental stages can result in several adverse outcomes. In this study, the exposure of Portuguese children to Cu, Co, I, Mo, Mn, Ni, As, Sb, Cd, Pb, Sn and Tl was evaluated through the analysis of first morning urine through ICP-MS. Furthermore, we attempted to determine possible exposure predictors. The study sample consisted of 54% girls and 46% boys, with a median age of 10 years; 61% were overweight/obese and were put on a nutritionally oriented diet. For I, half of the population was probably in deficiency status. The median urinary concentrations (μg/L) were Cu 21.9, Mo 54.6, Co 0.76, Mn 2.1, Ni 4.74, As 37.9, Sb 0.09, Cd 0.29, Pb 0.94, Sn 0.45, Tl 0.39 and I 125.5. The region was a significant predictor for Cu, Co, Ni, As and Tl. Child