Background: Non-Hispanic black (NHB) pregnant women disproportionately experience adverse birth outcomes compared to NH white (NHW) pregnant women. The positive effects of prenatal exercise on maternal and neonatal health may mitigate these disparities. This study evaluated the influence of prenatal exercise on racial/ethnic disparities in gestational age (GA), birthweight (BW), and risks of preterm birth (PTB), cesarean section (CS), and low-birthweight (LBW) neonates.Methods: This study performed a secondary data analysis using data from a 24-week, two-arm exercise intervention trial (ENHANCED by Mom). Women with singleton pregnancies (<16 weeks), aged 18-40 years, BMI between 18.5-34.99 kg/m2, and no preexisting health conditions were eligible. The aerobic exercisers (EX) participated in 150 minutes of moderate-intensity weekly exercise while non-exercising controls (CON) attended low-intensity stretching/breathing sessions. Data on GA, PTB (<37 weeks), BW, LBW (< 2.5 kg), and delivery mode were collected. Poisson, median and linear regressions were performed. Results: Participants with complete data (n=125) were eligible for analyses (EX: n=58, CON: n=67). NHB pregnant women delivered lighter neonates (β=-0.43 kg, 95% CI: -0.68, -0.18, p=0.001). After adjusting for prenatal exercise, racial/ethnic disparities in BW were reduced (β=-0.39 kg, 95% CI: -0.65, -0.13, p=0.004). Prenatal exercise reduced borderline significant racial/ethnic disparities in PTB (p=0.053) and GA (p=0.07) with no effects found for CS and LBW. Conclusions: The findings of this study demonstrate that prenatal exercise may attenuate the racial/ethnic disparities observed in neonatal BW, and possibly GA and PTB. Larger, diverse samples and inclusion of maternal biomarkers (e.g., cytokines) are encouraged to further evaluate these relationships.