In order to survey current management of oxygen in children with chronic lung disease (CLD) of prematurity in the United Kingdom and Ireland, 260 questionnaires asking about criteria that were considered important when removing supplemental oxygen from a child with CLD were sent to consultant paediatricians identified as being likely to be involved in the follow-up of children with CLD. A total of 120 questionnaires were returned from 114 centres. The factors that were considered important when removal of the patient's supplemental oxygen was being considered were: the oxygen saturation level in 100% responders; the respiratory rate in 62%; the heart rate in 37%; the length of time that the child had been in oxygen in 25%; changes on the chest radiograph in 22%; capillary blood gases in 18%, and arterial blood gases in 7%. The specific oxygen saturation level above which it was felt that the patient could stop oxygen therapy ranged from 85% to 98% (mean 93%). The situations which would prevent discontinuation of oxygen were: desaturation while feeding/ sleeping or exercising in 95% responders; failure to gain weight in 78%; presence of pulmonary hypertension in 62%, the parents' opinion or perception of their child's needs for supplemental oxygen in 58%; recent withdrawal of steroid therapy in 52%; a recent infection of the respiratory tract in 42%; history of cyanotic spells in 28%; and the advent of winter in 23%. Conclusion: there is an enormous variety of practice with regard to the management of supplemental oxygen for children with chronic lung disease suggesting an urgent need for research and evidence-based guidelines.