The prevalence of obesity in children with congenital heart disease (CHD) is greater than 25%, putting these patients at-risk for increased surgical morbidity and mortality. Our goal was to determine the association between CHD complexity, sociodemographic factors, and obesity. Our hypothesis was that among CHD patients, the odds of obesity would be highest in older children with simple CHD, and in all children with a lower socioeconomic status. We conducted a retrospective cohort study, reviewing electronic medical records of children aged 2-17 years from over 50 outpatient pediatric clinics in Houston, TX. Children were classified as simple or moderate/complex CHD, and obesity was defined by BMI ≥ 95th percentile for age and sex. Logistic regression was used to determine the association between sociodemographic factors and CHD complexity with obesity. We identified 648 CHD and 369,776 non-CHD patients. Children with simple CHD had a similar odds of obesity as non-CHD children. Children with CHD had a higher prevalence of obesity if they were older, male, Black, Hispanic, and publicly insured. Children with moderate/complex CHD had lower odds of obesity [OR 0.24 (95% CI 0.07-0.73)], however their predicted probability of obesity approached that of the general population as they aged. Additionally, there was an incremental relationship with poverty and obesity [1.01 (1.01-1.01)]. Awareness of which patients with CHD are at highest risk of obesity may help in targeting interventions to assist at-risk patients maintain a healthy lifestyle., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)