Background and objetive: Obesity is a major concern in public health. The fact that most teenagers stop contacting the health system during this period of life prevents detection of this problem and its associated morbidity. The aim of this study is to measure the prevalence of obesity at 18. We also aimed to detect overweight, cardiovascular risk factors (CVRF) and association with CVRF in parents and siblings. Patients and method: The research includes 153 children followed up to 18 years old in a community health center. Measures of body mass index (BMI), waist perimeter, CVRF, and familiar history were taken. Results: The prevalence of obesity in our study group was 7.18%, (IC: 3.0-11.0), (6.25% male and 7.86% female). The prevalence of overweight was 18.3% (IC: 11.9-24.0), (26.56% male and 12.35% female). A familiy history of CVRF was found in 53.9% (IC: 46.1-61.9) of cases, including high blood pressure (25%), obesity (23.6%), dyslipemia (21.7%), and diabetes (7.2%). This finding was more prevalent in the obesity group (72.72%) than in those with overweight only (64.2%), or with normal weight (49.59%). A family history of obesity and diabetes in first-degree relatives was associated to obesity in the study group. Also, a family history of high blood pressure was associated to the presence of high blood pressure in this group. Conclusions: In order to detect obesity, overweight, and associated complications in young adults, specific attention to children and siblings of persons who present risk factors is recommended. Those with high blood pressure, diabetes or obesity have the higher risk. (C) 2010 Elsevier Espana, S.L. All rights reserved.