The objective of this study was to determine risk factors of overweight in children 12 months-old from a primary Health Center in Punta Arenas. Patients and Methods: The information of 93 children and their respective mothers was obtained from clinical records: pregnancy, newborn period, anthropometric data and type of food consumed during the first year of life. Results: The prevalence of overweight was 20.2 % and obesity was 9 % at 12 months age. The multivariate analysis demonstrated: overweight at 6 months (odds ratio (OR) = 9,08 confidence interval (CI) = 2,69-30,67), overweight at the end of pregnancy (OR = 5,91 CI = 1,05 - 33,42) and adolescent mother (OR= 11,59 CI= 1,27 - 105,46) were the associated factors to overweight at 12 months-old (W/H ³ 1). There was an interaction between being an adult mother having overweight at the end of pregnancy (OR: 5,44), while being an adolescent mother having overweight at the end of pregnancy was a protective factor (OR: 0,007). Conclusions: there was a high prevalence of overweight in the study population. Some of the associated factors could be prevented from the gestational period