The neurodevelopmental status of 171 very preterm infants was assessed at one and four years of age. At one year 17 had major impairments and 14 had minor ones. At four years the numbers had increased to 25 with major and 25 with minor impairments. Infants with no impairments at one year had a 4 per cent probability of a major impairment at four years, whereas infants with a major impairment had a 94 per cent probability. Infants who later proved to have major neuromotor impairments had been accurately identified at one year, as had infants with sensorineural hearing-loss. Infants with minor impairments of tone and reflexes at one year did not develop cerebral movement disorder, but as a group their scores on tests of cognitive functioning were low. An additional group of infants with cognitive impairments was identified who were unimpaired at one year. The emergence of cognitive deficits largely accounted for the increase in impairments between one and four years.