The high prevalence of overweight and obesity in children is one of the major health problems nowadays. Body mass and the proportion of fat tissue in the body can cause many health problems being too low or too high, so it is important to continuously regulate them from an early age. The main goal of this thesis was to examine and determine the nutritional status and to establish whether there are statistically significant sex differences in the nutritional status of preschool children. The sample of respondents includes 21 girls and 23 boys aged 6 to 7 from a kindergarten in Zagreb. The variables used in the research were: body height and mass, waist circumference, and the thickness of the skin folds of the upper arm and back. Based on the obtained data, the body mass index, the percentage of fat tissue and the ratio of waist circumference to body height were calculated. The obtained results were compared with standard percentile values for children of that age. The final results showed no statistically significant difference in nutritional status between the sexes, but higher percentage values of fat tissue are visible in girls compared to boys of preschool age. In order to ensure the proper growth, development and health of children, it is important to monitor the morphological features of children in practice so that timely intervention can be made and the possible development of health problems can be prevented.