The relation between the ultrasound appearance of the brain and neurodevelopmental outcome at eight years of age was investigated in 206 infants born between 1979 and 1982 at < 33 weeks gestation (600 to 2500g birthweights). Only 4 per cent of the 112 infants with normal scans at discharge from the neonatal unit developed major, disabling impairment. No significant adverse effect of uncomplicated periventricular haemorrhage was detected. The probability of a major impairment in infants with ventricular dilatation or hydrocephalus was 27 per cent, and 69 per cent in those with cerebral atrophy. 44 per cent of the children demonstrated significant differences in their cognitive processing skills, which appeared capable of affecting learning and may possibly have been caused by undetected hypoxic-ischaemic damage to callosal fibres.