In this study, we used MR-based estimation of abdominal fat distribution and the degree of adipocyte hypertrophy to study sex and ethnic differences in 4.5-year-old Asian children. Our results show sexual dimorphism in abdominal fat distribution in preschool children. Girls had higher subcutaneous fat depot volumes and lower adipose tissue hydration than boys. We also found that at 4.5 years, both deep and superficial subcutaneous fat volumes in Indian children were higher, while the ethnic difference in internal fat was non-significant. These differences may help explain why Indians are more susceptible to metabolic and cardiovascular diseases.