Objective: To determine the relationship between caries and overall child development in three-year-old children in the cities of Linares and Talca, Chile, 2014-2015. Method: Cross-sectional study conducted in a sample of 170 preschool children attending daycare centers in Linares and Talca. Four dimensions of child development (language, cognition, motor skills and socio-emotional development) were qualitatively assessed using the child learning and development test (TADI, for its acronym in Spanish). Nutritional development was calculated with the weight/height index. Caries history was assessed by the dmft index and compromised tissue quantification. Statistical analysis was performed using Pearson's rho, ANOVA, Student’s t-test, Fisher’s exact test and Kruskal-Wallis. Results: A negative linear correlation was observed between dmft and total TADI score (r=- 0.20, p=0.00), and the dimensions of language (r=- 0.19, p=0.01), cognition (r=-0.18, p=0.02) and socio-emotional development (r=- 0.21, p=0.01). Preschoolers with a dmft of >6.5 had a lower average TADI score than those with a dmft of <2.6 (p=0.009). There were no statistically significant differences in the level of compromised tissue quantification between preschool children with normal and altered development. No statistically significant association between dmft and nutritional development was found. Conclusion: A relationship between caries severity and overall child development in three-year-old preschool children was observed. Longitudinal studies are required to assess causality.