A healthy and balanced diet is very important at all stages of life, but specially in adolescence. The purpose of this master's thesis was to evaluate dietary intake and body composition of adolescents (13 to 15 years old) at five different Slovenian primary schools. Our research started at the beggining of school year 2017/18. At PTA meetings, parents were briefed on the research and they were invited to participate; 63 parents and their children (34 boys and 29 girls) decided to take part in the survey. The average age of boys was 13.7 and the average age of girls was 13.8. We obtained the information on eating habits, amounts of food, energy intakes and intakes of other macro and micro nutrients by using food frequency and socio-demographic questionnaires. Body composition data (body height, weight and triceps skinfold) were collected in schools from sport-educational charts. Additionally, we calculated body fat percentage. In our sample of children, it is statistically significant that children in Prekmurje region consume less sodium (p = 0.04) and thus also less salt and less sugar (0.038) than children from other parts of Slovenia. There was no significant difference between the BMI (p = 0.573) and the BFP (p = 0,585) of adolescents in Prekmurje region compared to adolescents in other parts of Slovenia. The average energy intake did not meet the Reference values for nutrients intake (boys 2600 kcal/day, girls 2200 kcal/day, PAL = 1.6), as it was too low for both boys and girls. The intake of carbohydrates and dietary fibres was too low. In light of the recommendations, the intake of saturated fatty acids was satisfactory and the intake of monounsaturated and polyunsaturated fatty acids was too low. The analysis of micronutrients showed that adolescents had inadequate intakes of vitamins A and D, calcium, iodine and magnesium, but the intake of vitamins B9 and C was adequate.