Introduction. There are few published data on the efficacy of systemic corticosteroids in preterm infants with very severe forms of bronchopulmonary dysplasia (BPD), requiring respiratory support after 3 months of age. The aim of this study was to report the use of pulses of methylprednisolone in this population and its consequences on the level of respiratory support. Methods. This retrospective monocentre study included infants over three months of age with severe BPD who received at least one pulse of methylprednisolone (300mg/m²/day IV over three days). The primary outcome was the evolution of the pulmonary severity score (PSS) during the three months preceding and the five months following the first pulse. The evolution of the median PSS over time was analysed using linear segmented regression for interrupted time series. Results. Ten infants were included. During the three months preceding the first pulse, a significant increase in the median PSS was observed (p=0.01), followed by a progressive decrease during the five months after administration of the first pulse (p<0.01). Greater effects were observed in more severe infants requiring mechanical or non-invasive ventilation than in those receiving supplemental oxygen through nasal cannula. Conclusion. High-dose IV pulses of methylprednisolone were associated with a decrease in the level of respiratory support required by infants with very severe forms of BPD, with a greater effect in those on mechanical or non-invasive ventilation. Further studies are warranted to confirm these preliminary results and assess the long-term safety of this therapy.