Bronchopulmonary dysplasia was first described by Northway et al. in 1967. The disease has changed over time following advances in neonatal care. The incidence of BPD has slightly increased over the past decades due to higher survival rates at the limits of viability. Nowadays, each year about 12 % of all infants born very preterm are diagnosed with BPD in Switzerland. The debate on how to best define BPD is still ongoing, despite multiple revisions of the initial BPD definition.