Introduction: Current Chilean childhood obesity fi res are within the highest in the world., Objective: To describe the nutritional status of Quilpué schoolchildren and its relationship with demographic and socioeconomic variables., Methods: The nutritional status (OMS 2007) of 1091 schoolchildren was assessed using measurements of height and weight obtained in the "Pilot School Health Program" conducted in the schools of the Municipal Corporation of Quilpué, which included pupils from kindergarten to 4th grade. The program described above, as well as SINAE databases, were used for the Healthcare and School Vulnerability Index (SVI) variables, respectively, as well as the the number of hours of physical education, type of lunches, and the presence of vendors at school, were obtained using a questionnaire in schools., Results: Obesity was observed in 26.3% of students, and a further 27.7% were overweight. Obesity was more frequent in boys (32.3%) compared to girls (20.1%) (P<.01); in third grade (31.8%) (P=.01); if lunches were parental choices (26.7%) (P<.01); and with the presence of school vendors (26.3%) (P=.01). No significant differences in socioeconomic status regarding BMI were found, but the most vulnerable children (municipal schools, high SVI, Fonasa A healthcare) had lower average height and higher rates of chronic malnutrition (height <-2 SD)., Conclusions: A high prevalence of obesity was found in this study, which highlights the need for monitoring and nutrtional intervention strategies at school age (which once finalized, the Healthy Child Surveillance does not carry out any more controls), taking into account the most vulnerable sectors., (Copyright © 2015. Publicado por Elsevier España, S.L.U.)