Bronchopulmonary dysplasia (BPD) is one of the most important sequelae of premature birth. There is concern that in some patients, lung injuries early in life may have lifelong consequences. In this retrospective observational cohort study, lung function evolution in children with BPD was investigated from childhood to young adulthood. Data from 355 pulmonary function tests (PFT) in 24 patients were analyzed, with a median age at first PFT of 7.6 years and at last PFT 18.2 years. FEV and FEV/FVC were below the 5th percentile in respectively 18 and 13/24 patients. Comparing first and last measurement, there was significant worsening in FEV from a mean of 71.3% pred (SD 18.3) to 66.7% pred (SD 21.7) (p < 0.05) and in FEV/FVC from 85.4% pred (SD 15.2) to 79.8% pred (SD 17.3) (p = 0.01). Evaluation of the individual lung function changes with linear regression showed deterioration in FEV, FVC, and FEV/FVC in respectively 17, 13, and 17/24 patients. Total group analysis showed significant deterioration in FEV (- 0.7%/year, p = 0.002) and FEV/FVC (- 0.5%/year, p = 0.01). None of the 11 patients born up to 1990 improved in FEV vs 7 of the 13 patients born after 1990 (p = 0.006).Conclusion: This points out to further deterioration of the lung function during childhood in this selected group of children with BPD.What is Known:• Data on longitudinal changes in lung function in children with BPD are scarce.What is New:• In children with BPD at the severe end of the disease spectrum, lung function does not improve over time. On the contrary, in two-thirds of the subjects studied FEVand FEV/FVC worsen over time.• Lung function evolution towards adulthood was somewhat more favorable in children born after 1990 compared with those born earlier, probably reflecting improvements in neonatal care in subjects with new type BPD.