Objective: To evaluate the association between furosemide exposure and risk of bronchopulmonary dysplasia (BPD). Study design: This was a retrospective cohort study of infants (2004-2015) 23-29 weeks gestational age and 501-1249 g birth weight. We compared demographic and clinical characteristics of infants exposed and not exposed to furosemide between postnatal day 7 and 36 weeks postmenstrual age. We examined the association between furosemide exposure and 2 outcomes: BPD and BPD or death. We performed multivariable probit regression models that included demographic and clinical variables in addition to 2 instrumental variables furosemide exposure by discharge year; and furosemide exposure by site. Results: Of 37,693 included infants, 19,235 (51%) were exposed to furosemide; these infants were more premature and had higher respiratory support. Of 33,760 infants who survived to BPD evaluation, 15,954 (47%) had BPD. An increase in the proportion of furosemide exposure days by 10 percentage points was associated with a decrease in both the incidence of BPD (4.6 percentage points, P = .001), and BPD or death (3.7 percentage points, P=0.01). Conclusion: More days of furosemide exposure between postnatal day 7 and 36 weeks was associated with decreased risk of BPD and a combined outcome of BPD or death.