Congenital heart defects (CHDs) are a leading cause of infant morbidity and mortality. Infants with CHDs have increased risk of preterm birth (PTB) compared to infants without birth defects. Although non-Hispanic (NH) Blacks are more likely to be born preterm and Hispanics have rates similar to those of PTB to NH-Whites, it is unknown if this pattern is present for infants with specific types of CHDs. Our intent was to determine if defect-specific risk of PTB varies by maternal race/ethnicity among infants with CHDs. We conducted a retrospective cohort study with 14,888 singleton infants from the Florida Birth Defects Registry, born in 1998-2003 to resident NH-White, NH-Black, and Hispanic women aged 15-49, diagnosed with 11 CHDs. Covariates were taken from Florida live birth certificates. PTB was defined as 20-36 weeks of gestation. Odds ratios (OR) and P-values were calculated from defect-specific multivariable logistic regression models; statistical significance was set at P < 0.002. The greatest risk of PTB was for NH-Black infants with conotruncal CHDs. NH-Blacks with common truncus, transposition of the great vessels, and tetralogy of Fallot had increased risk of PTB compared to NH-Whites (OR = 4.8, P = 0.015; OR = 3.1, P = 0.004; and OR = 2.0, P = 0.005, respectively). Hispanics with conotruncal CHDs had almost a twofold risk of PTB compared to NH-Whites (P > 0.002). NH-Blacks with tricuspid valve atresia/stenosis had 4.1 times (P = 0.034) and Hispanics had 2.1 times (P = 0.314) the risk for PTB compared to NH-Whites. NH-Blacks with hypoplastic left heart syndrome had 2.0 times (P = 0.047) the risk for PTB as NH-Whites. Both NH-Black and Hispanic infants with CHDs may be at increased risk of PTB, depending on the type of CHD, but the etiology is unknown. Future research is needed to further examine this complex relationship.