Bronchopulmonary dysplasia (BPD) is often complicated by pulmonary hypertension (PH). We investigated three biomarkers potentially suitable as screening markers for extremely preterm infants at risk of BPD-associated PH. In this prospective observational cohort study conducted in a tertiary neonatal intensive care unit, 83 preterm infants with BPD born <28 weeks gestation and still inpatients at 36 weeks corrected age received an echocardiogram and blood tests of B-type natriuretic peptide (BNP), troponin I, and YKL-40. Infants were analysed according echocardiographic evidence of tricuspid regurgitation (TR). 30 infants had evidence of TR on echocardiogram at 36 weeks corrected age. Infants with or without TR had similar baseline demographics: mean±SD gestational age 261±12 weeks versus 261±11 weeks, and mean±SD birth weight 830±206g versus 815±187g, respectively. There was no difference in duration of respiratory support. The mean±SD right ventricular systolic pressure of infants with evidence of TR was 40±16 mmHg. BNP was the only biomarker that proved to be significantly higher in infants with evidence of TR: median (IQR) serum level 54.5 (35-105) versus 41.5 (30-59) pg/ml, p=0.043. Subgroup analysis of infants with severe BPD requiring discharge on home oxygen or BPD-related mortality revealed similar results. There was no difference between groups for troponin I and YKL-40. In conclusion, increased serum levels of BNP were associated with evidence of TR at 36 weeks corrected gestational age in extremely preterm infants, suggesting a potential role as a screening biomarker for BPD-associated PH.