Purpose: Early childhood caries (ECC) and childhood obesity are among the most prevalent health conditions affecting children. ECC is associated with obesity through the common risk factor of sugar consumption. The present study aimed to assess the association between ECC and obesity in preschool children. Materials and Methods: A cross-sectional study was conducted among 1250 preschool children (698 girls, 552 boys; mean age: 4.3 [1.1] years). The children’s body mass index was determined (BMI: weight/height in kg/m2). The World Health Organization criteria were used for the diagnosis of caries. Multivariable logistic regression was used to analyse the relationship between ECC prevalence and childhood obesity. Results: ECC was detected in 929 (74.3%) children. The mean dmft and dmfs was 5.91 (1.13) and 8.92 (2.07), respectively. The multiple regression model showed a statistically significant association between ECC prevalence and obesity with an adjusted odds ratio (OR) of 2.59 (95% CI: 1.88 – 3.57; P = 0.001). The logistic regression model showed that in children with a monthly family income > $2666, sugar consumption, preterm low birth-weight/full-term low birth-weight (PTLBW/FTLBW), and toothbrushing frequency ≤ 1 time/day were statistically significantly associated with ECC prevalence. Conclusion: ECC was positively associated with obesity.