OBJECTIVE The purpose of this study was to investigate the association between dental caries and obesity in preschool children. METHODS A total of 329 preschool children were recruited from nine day care centers. A qualified dentist examined the oral health of each child and a caries score was recorded. Anthropometric measurements included body weight, height, triceps skinfold thickness, and body fat. Body mass index, and weight-for-height index were calculated. Parents or guardians answered a questionnaire regarding their children's dietary patterns, oral hygiene habits, and medical history, as well as parental practices and attitudes towards their children's oral health. RESULTS The prevalence of dental caries was 73% in this study. Fourteen percent of the children were overweight or obese. The caries scores were not significantly different according to weight-for-height index categories. After taking into account important factors in the multiple regression models, body mass index and weight-for-height index, respectively, were not significantly associated with dental caries. CONCLUSIONS This study showed that obesity was not significantly associated with dental caries in preschool children.