Objectives: To analyse secular changes (2010-2020) in skinfold thickness in children and adolescents in different BMI categories. Methods: The study group consisted of 3-16-year olds included in two cross-sectional studies. Measurements included height, weight and 5 skinfolds. The Body Mass Index was used to categorize participants into low (underweight), normal or excess (overweight and obesity) weight groups based on IOTF cut-off points. Differences of skinfold thicknesses between both cohorts, within each of the weight status categories, were assessed using two-way ANOVA and Tukey's tests. Results: In both sexes, there was a negative secular trend in limb adiposity among the normal weight and underweight cohorts. However, in both of those subpopulations individuals examined in 2020 had greater trunk adiposity, in comparison to their counterparts examined in 2010. Declining limb adiposity was also present in the overweight category. Although, trunk adiposity among individuals with overweight was generally comparable in both cohorts. Conclusions: There was a tendency towards normal weight obesity, particularly excess abdominal adiposity, among the 2020 cohort. These findings further suggest that using only the BMI, without taking into consideration tissue composition of the body, may result in misclassification of children and adolescents with high adiposity as normal-weight.