The follow-up records of 605 infants with birth weights of less than 1,500 g, with data available for 2 years after birth, were examined for evidence of abnormal pulmonary signs or symptoms. A total of 119 infants were identified and the neonatal oxygen requirements of these infants were compared with those of 486 infants who had normal pulmonary function. A requirement for oxygen at 28 days of life had a positive predictive value for abnormal pulmonary findings at the time of follow-up of only 38%, whereas 31% of those with normal pulmonary findings at the time of follow-up were still receiving oxygen at this age. The need for oxygen at 28 days was a good predictor of abnormal findings in infants of greater than or equal to 30 weeks' gestational age at birth but became increasingly less useful as gestational age decreased. It was found that, irrespective of gestational age at birth, the requirement for additional oxygen at 36 weeks' corrected postnatal gestational age was a better predictor of abnormal outcome, increasing the positive predictive value to 63%. The prediction of a normal outcome remained 90% for infants not receiving oxygen at this corrected gestational age.