Purpose: Dental caries and obesity are multifactorial diseases of high prevalence in Chilean child population, and both are preventable from early age. They share association with diet habits and socio-cultural determinants. The objective of this study was to determine the coexistence between caries and obesity in 6 year-old schoolchildren from the Metropolitan Region of Santiago, Chile. Methods: A sample was composed by 571 6 year-old schoolchildren from the fluoridated communes of the Metropolitan Region of Santiago, Chile, in 2004-2005. Caries diagnosis was performed by using the WHO criteria for epidemiological studies. Nutritional diagnosis was carried out according to BMI/age and sex in relation to CDC-NCHS curves, considering obese children with a =95 percentile. Socioeconomic level (SEL) and sex were recorded. Results: No statistically significant difference was found between caries history and nutritional status (NS) (P=0.837), in both primary and permanent dentition (P=0.306).There was no risk association (OR 0.88; IC 0.60-1.28; 95%). Overweight children had less caries prevalence and history than normal weight and obese children. No relationship was found at the multivariate analysis between NS, SEL and caries occurrence. Conclusion: Obesity is not related to dental caries in this sample. Overweight children had less caries prevalence and severity. Copyright: © 2011 Yévenes et al.; licensee EDIPUCRS.