Most young children by nature love to move, are physically ready at first and can’t wait to be active. A preschool child is full of unstoppable energy and uses every opportunity that comes his way to run, jump, spin or climb. Due to the accelerated digitalization, which encourages a sedentary lifestyle, there has been an increasing number of obese children and young people in recent decades. They do not move enough and spend less and less time in open spaces. Preschool age is not too early to introduce a child to sports, it is only important to adapt it to the child's age, interests and needs, and it will then play a key role in their healthy growth and development. Early childhood is suitable for stimulating the development of morphological characteristics and we can influence them if we approach the child with physical activity that is applied to his age and respects his individual characteristics. In order to determine whether there are differences in anthropometric characteristics with respect to physical activity, a study was conducted in preschool children. Two preschool groups of children who participated in the research are participants in the kindergarten Trešnjevka in Zagreb. The sample consisted of 30 preschool children. In order to assess the relationship between the level of physical activity and anthropometric characteristics, a survey questionnaire was conducted for parents where they met the amount of physical activity of their child and in cooperation with the health manager children were measured body height and weight. Based on the obtained data, the body mass index (BMI) of an individual child was calculated and compared with the graph in order to determine the so-called percentiles. Percentiles show the relative state of a child’s BMI relative to children of the same age and gender. The results of the research showed that there is no statistically significant difference in the anthropometric characteristics of children with regard to the amount of their physical activity, ie between children who are involved and children who are not involved in some sports activities. It was also shown that there is no statistically significant correlation between the measured anthropometric characteristics and the quality of leisure time. After calculating the BMI of each child, it could be confirmed that it is generally lower in children who are more engaged in physical activity and that it is generally higher if children are not included in any sports program and if the child is not active in leisure time.