An analysis was conducted to evaluate if the severity of caries is associated with protein-calorie malnutrition in preschool children. The cross-sectional study was performed on a retrospective cohort of 625 children aged 24-71 months attending daycare centers in São Luís, Maranhão. A hierarchical model was evaluated at five levels: 1.) Socio-economic variables (economic group, mother's educational level and skin color); 2) Access variables; 3) Low birth weight (LBW) and exclusive breastfeeding; 4) Weight per height at 12 months; and 5) Severity of caries and albumin (Alb) levels. The outcome was protein-calorie malnourishment (weight per height z score < -2). The prevalence of outcome was 5.0% and the prevalence of caries was 32%. At the first level, the variables were not associated with the outcome, but the economic group was maintained until the final model. The variables in the second and third levels were not significant. At the fourth level, weight for height at 12 months was not significant, but was maintained until the final model. In the last level, severity of caries was positively associated with malnourishment. The association between severity of caries and malnourishment suggest that oral health should be integrated with public health care policies for children.