Obesity in children has been one of the leading public health problems for many years. It represents an important risk factor for the development of many chronic diseases, and can affect the child's mental health. Health consequences caused by obesity also represent a financial burden to the health system, which is why a constant monitoring of the occurrence of obesity and the risk factors for its development is extremely important. The aim of this paper was to determine the prevalence of overweight, obesity and risk factors for their development in children (8-8.9 years) in Croatia within defined socioeconomic groups, and to determine whether or not there is a correlation between this variables. The results showed that the prevalence of overweight and obesity in Croatia in school year 2015./2016. was 34.7% among children from the families of low, 36.9% among children from the families of middle and 33.2% among children from the families of high socioeconomic status. The correlation between the prevalence of overweight and obesity in children and their affiliation to the socioeconomic group does not show statistical significance (phi = 0.038; p = 0.202). The risk factor related to time spent in organized sports activities less than two hours per week shows the highest correlation strenght with child's affiliation to the socioeconomic group (phi = 0.252; p <0.001).