We evaluated the association between implementation of state-mandated pulse oximetry screening (POS) and rates of emergency hospitalizations among infants with Critical Congenital Heart Disease (CCHD) and assessed differences in that association across race/ethnicity. We hypothesized that emergency hospitalizations among infants with CCHD decreased after implementation of mandated POS and that the reduction was larger among racial and ethnic minorities compared to non-Hispanic Whites. We utilized statewide inpatient databases from Arizona, California, Kentucky, New Jersey, New York, and Washington State (2010-2014). A difference-in-differences model with negative binomial regression was used. We identified patients with CCHD whose hospitalizations between three days and three months of life were coded as emergency or urgent or occurred through the emergency department. Numbers of emergency hospitalizations aggregated by month and state were used as outcomes. The intervention variable was an implementation of state-mandated POS. Difference in association across race/ethnicity was evaluated with interaction terms between the binary variable indicating the mandatory policy period and each race/ethnicity group. The model was adjusted for state-specific variables, such as percent of female infants and percent of private insurance. We identified 9,147 CCHD emergency hospitalizations. Among non-Hispanic Whites, there was a 22% (Confidence Interval [CI] 6%-36%) decline in CCHD emergency hospitalizations after implementation of mandated POS, on average. This decline was 65% less among non-Hispanic Blacks compared to non-Hispanic Whites. Our study detected an attenuated association with decreased number of emergency hospitalizations among Black compared to White infants. Further research is needed to clarify this disparity.