A prospective 2-year follow-up study of infants with birth weights of less than 1250 g was undertaken at Groote Schuur Hospital Neonatal Intensive Care Unit. For a 12-month period beginning July 1988, all live infants born at Groote Schuur Hospital or referred to the Neonatal Intensive Care Unit were included in the study cohort. The aim of the study was to document the morbidity, mortality, and neurodevelopmental outcome of these infants to 2 years of age. Of 235 liveborn infants, 143 (61%) survived to discharge. One hundred twenty-six infants were born weighing less than 1000 g; 42% survived to discharge. One hundred nine infants weighed 1000 g or more at birth, and 83% survived to discharge. Better survival was documented for infants whose mothers attended antenatal care, who weighed more than 900 g, and who were of greater than 30 weeks' gestation. Eleven infants died in the first 6 months after discharge. One hundred six infants (83% of survivors) underwent Griffiths developmental testing and clinical assessment at 1 year of age. Ninety-six (91%) of these survivors were seen and tested at 2 years of age. Of the 106 infants assessed at 1 year of age, 6 infants had cerebral palsy, 6 were globally developmentally delayed without signs of cerebral palsy, and 1 infant showed significant motor delay with a normal developmental quotient. At 2 years of age 1 additional infant had cerebral palsy and 9 more infants are likely to be mentally retarded. At 2 years of age the major handicap rate was, therefore, 22% . Sixty-nine percent of surviving infants, and all but 1 of the infants with cerebral palsy, were underweight for gestational age at birth. There was a tendency for these underweight-for-gestational-age infants to score less well at 2 years of age. Infants who received ventilation and infants with a birth weight of less than 1000 g were not found to score less well than other infants in the cohort.