The fundamental components that contribute to a high level of life quality refer to the aerobic capacities in correlation with a high level of physical activity. Physical activity is considered one of the basic human functions and its relevance is reflected in health benefits. High quality of life is influenced by factors that relate to physical readiness, body composition and physical activity. The goal of this research is to determine the relationship between the quality of life and aerobic functional capacity as well as their differences considering primary education students’ nutritional status. The partial goal of this research is to determine primary education students’ level of aerobic capacity and the quality of life indicators considering the macro-regional characteristics of the Republic of Croatia, as well as to ascertain possible differences in the aerobic capacity in subsamples defined by gender. The research involves a stratified sample of students categorized according to three Croatian macro-regions (Continental, the City of Zagreb, Adriatic). Research participants were 651 fourth grade students (48.54 % girls and 51.46 % boys). Students’ age was 10.30 ± 0.47 years. The research was conducted in the second term of 2021/2022 school year in May and June. The research was conducted in accordance with the ethical principles prescribed by the Code of Ethics of the University of Zagreb and the Code of Ethics in Research with children in accordance with the Decision by the Ethics committee of the Faculty of Teacher Education University of Zagreb. The Croatian version of the Quality of life questionnaire KIDSCREEN-10 was used to ascertain children’s subjective health and well-being. Aerobic capacity was evaluated using a 20 m multistage run test (20 m MSRT Shuttle run test). Body height was measured with a stadiometer while the body mass, BMI, fat percentage, degree of obesity (%) and muscle mass (kg) were all measured using a dual frequency full-body composition analyser (TANITA DC-360P). Waist and hip circumference was measured using a centimetre tape, and the waist-to-hip ratio (WHR index) was calculated. The classification of the participants according to the fat percentage was done according to McCarthy, Cole, Fry, Jebb, and Prentice 2006) with predefined centile curve specific to children, considering gender and age along with the division based on body mass – normal body mass (2-85 centile), high body mass (85-95 centile) and obesity (over 95 centile).A simple linear regression analysis was done to determine the relationship between the students’ quality of life as a predictor and their aerobic capacity as the criterion. Furthermore, the significance of the differences between the formed subsamples considering the nutritional status (normal body mass, high body mass, obesity) and aerobic capacity, as well as the quality of life in primary education students was tested using a univariate analysis of variance - ANOVA. The significance of differences in aerobic capacity and the quality of life according to gender and quality of life and aerobic capacity with regard to macro-region was also tested by univariate analysis of variance - ANOVA. The statistical significance level was set at p < 0.05. Data processing was done by STATISTICA software version 14.0.0.15., TIBCO Software Inc.The results show that the participants perceive their quality of life as relatively high with a mean score of 4.33±0.48. The highest quality of life assessments refer to the category of relationship with parents or family, as well as having fun with friends, and loneliness. The lowest values are visible in the dimensions of success in school, free time, and bad mood. Using linear regression analysis, a positive correlation between the students’ quality of life and aerobic capacity was determined and therefore it may be proposed that increasing the aerobic capacity can significantly affect the students’ quality of life. The results of the variable for estimating the maximal oxygen uptake (VO2max mL/kg/min) used in estimating aerobic capacity in boys is 45.79 while in girls it is 44.50 The results of the maximal oxygen uptake (VO2max mL/kg/min) in the total sample is 45.16. Within the test sample, 79.11% of students had a normal nutritional status while 12.60 % were overweight and 8.29 % were obese. The results show that there is a significant difference in the aerobic capacity between the students belonging to these three nutritional status groups. When determining individual differences, it is apparent that there is considerable difference between the students who have a normal nutritional status (45.74) and those with excessive body weight (43.26). It is also apparent, that students with a normal nutritional status have significantly better values of aerobic capacity than those who are obese (42.25). Furthermore, a significant difference in the self-evaluation of the quality of life has been determined between students who have a normal nutritional status and those who are overweight or obese. Observing the differences concerning the aerobic capacity, it is evident that the students who live in economically better developed regions of the country, primarily in the City of Zagreb and the Adriatic region, have better results than those living in the Continental region of Croatia. Also, even though it was determined that the quality of life does not differ significantly across the regions, students living in the Adriatic macro-region have nominally better results. Statistically, boys have significantly better results when it comes to aerobic capacity than girls do, but the self-evaluation of the quality of life does not differ much across genders. A low level of physical fitness and aerobic capacity, along with a poor quality of body composition and a low quality of life can be characterized as a reversible condition that can be amended through certain changes in lifestyle, which involve a healthy diet and increased physical activity. Changing one’s lifestyle can also contribute to a higher quality lifestyle in adulthood. Using exercises that induce the development of aerobic capacity in children and young people can prevent obesity and reduce other factors of cardiovascular risk and can therefore be an important factor in improving one’s health. This research could be used as a basis for planning future preventive programs for students in primary education, that would have increasing aerobic capacity as its goal. Schools as educational institutions have the ability to implement physical activity intervention programs into their curriculum with the purpose of increasing students’ aerobic capacity, which can have numerous health benefits. These intervention programs could have a positive effect on the development of aerobic capacity in children in their present lives, but also in their adulthood, where the negative impact on general health can be significantly minimized.