Objetive: analyze the prevalence of overweight and obesity, the level of physical activity and self-esteem of the school population of fourth, fifth and sixth grades of the Central District of Heredia. Method: The descriptive-comparative and transversal study analyzed 442 children, 234 boys and 208 girls between 9 and 13 years old. It was measured the weight and height to calculate the body mass index, the Physical Activity Questionnaire for Children (PAQ-C) and Lawrence's Self-Esteem Questionnaire (LAWSEQ). Results: the results suggest 20.6 % of infants with overweight and 13.6 % with obesity, 29.4 % indicated a low level of physical activity and 26.7 % with low self-esteem. In addition, boys report a higher level of physical activity compared to girls (F (9) =2.55; p=0.007). Conclusions: According to the objective, the prevalence of overweight and obesity in girls and boys was 34.2 %, 30 % presented high levels of sedentary lifestyle and 27 % low self-esteem. These information indicate the importance of generating intervention options is demonstrated in the different levels of education with the aim of palliate the results of this research, working as a team with government organization in the country.

Keywords: Child's Health, body weight, human movement, self-perception