 Within 2 years 850 infants of 23-27 weeks GA will be randomised during the first 12 hours of life to Budesonide or placebo to prevent BPD. Study drugs will be administered via Aerochamber and continued until infants are either off supplementary oxygen and positive pressure support or have reached a GA of 32 07 weeks regardless of ventilatory status. The primary outcome of survival without BPD will be determined at 36 weeks GA and BPD will be defined according to the physiological definition. Study patients will be followed and neurodevelopmental outcomes will be assessed at a corrected age of 18-22 months. 