Introduction: Although mortality has declined among infants with congenital heart disease (CHD), racial/ethnic and sociodemographic disparities persist. The child opportunity index (COI) is a census-based metric of neighborhood conditions based on education, health/environment, and social/economic domains. We sought to determine the impact of COI on neonatal and 1-year mortality of infants with CHD. Hypothesis: We hypothesized that neighborhood sociodemographic factors as measured by COI would have a greater impact on longer-term outcomes. Methods: This is a retrospective population-based cohort in California (2011-2017) of infants with CHD who underwent a cardiac intervention in the first year of life. COI was categorized into high, moderate, and low. Each COI domain was evaluated. The primary outcomes included 1-year mortality, neonatal mortality prior to 30 days of life, and days alive out of hospital in the first year of life (DAOOH). Uni- and multivariable logistic and linear regression were used. Results: The sample included 9,729 infants with an overall 1-year mortality rate of 8.2% and neonatal mortality rate of 3.5%. After adjusting for race/ethnicity, maternal age, sex, CHD severity (RACHS-1 category), birth weight z-score, and gestational age at birth, the odds of 1-year mortality were significantly higher among infants from low compared to high COI (1.37, 95%CI: 1.13, 1.67). In contrast, the adjusted odds of neonatal mortality were not different in low compared to high COI (1.20, 95%CI:0.89,1.61). Low and moderate COI groups had significantly lower DAOOH compared to high COI (low: -10.30, 95%CI: -15.2, -5.4; moderate: -7.43, 95%CI: -12.96, -1.89). Results were similar for each COI domain ( Figure 1). Conclusion: Neighborhood factors reflecting the home environment influence outcomes beyond the neonatal period. Future studies are needed to determine whether targeting domains of the COI will mitigate ongoing risks of poor CHD outcomes.