In a long-term prospective control study, 20 extremely low-birth-weight infants with birth weights between 500 and 900 g (mean 755 +/- 109 g) and gestational ages between 24 and 30 weeks (mean 26.2 +/- 1.8 weeks) were compared with 20 full-term infants, after the first year of life for growth, development and continuing morbidity after discharge from the intensive care unit. The total rate of neurological abnormalities was 17%; the rate of infantile post-hemorrhagic hydrocephalus requiring shunt operations was 8.7%, while 13% had retinopathy of prematurity with vision deficit, but none was blind. The hospital readmission rate was 70%, but for most infants only one or a few readmissions were needed whereas three infants with chronic lung disorders required frequent hospital readmissions, mainly for respiratory infections. Apart from 4 infants with major cerebral neonatal complications, 16 of 20 extremely low-birth-weight infants (80%) showed development within the normal range at one year of age, although with delay in some areas in comparison with full-term control infants. Follow-up into preschool and school age is in progress. We cautiously suggest that the results at the one year follow-up do indicate a possible favourable long-term outcome for many of these extremely low-birth-weight infants with normal cognitive development and with no major neurological sequelae.