To estimate the effect of clinical chorioamnionitis on the risk of patent ductus arteriosus (PDA). A secondary analysis of all deliveries >23 gestational weeks from the U.S. Consortium on Safe Labor (CSL) study. The primary exposure was a clinical diagnosis of chorioamnionitis, and the outcome was a diagnosis of PDA. Generalized estimating equations with estimated error variance for women with multiple deliveries were utilized. Models adjusted for age, race, region, delivery year, body mass index, infant sex, multiple gestation, mode of delivery, and antenatal corticosteroid exposure. Among 228,438 deliveries, a diagnosis of PDA was more frequent with chorioamnionitis exposure versus without (9.2% vs. 3.0%; OR: 3.25; 95% CI: 2.92-3.62). Chorioamnionitis was associated with higher adjusted odds of PDA (AOR: 2.18; 95% CI: 1.93-2.45). In sensitivity analyses, the association between chorioamnionitis and PDA held after adjustment for gestational age at delivery (AOR: 1.28; 95% CI: 1.13-1.44). Chorioamnionitis was associated with increased odds of PDA. Robust exposure and outcome ascertainment with careful assessment of confounding is needed to further investigate this epidemiologic association.