The brains of 50 consecutively admitted infants weighing 1250 g or less at birth were serially examined beyond the neonatal period for periventricular haemorrhage and for periventricular leukomalacia with real-time ultrasound. There was significant correlation between the presence or absence and the severity of haemorrhage with survival. A prospective neurodevelopmental assessment was completed at 2 years of age, corrected for prematurity, on all survivors. None of the 20 survivors with normal scans or germinal layer haemorrhages had evidence of major disability and all four survivors with intracerebral haemorrhage or periventricular leukomalacia had major disability. The mental performance on the Bayley scales of infant development was also significantly worse in the latter group. Six of the eight survivors with intraventricular haemorrhage had no major disability, including three who had post-haemorrhagic hydrocephalus. Our results showed that cerebral ultrasound detection of brain pathology is a good predictor of neurodevelopmental outcome in such extremely low birthweight infants. However, as the maximum extent of periventricular haemorrhage may develop beyond one week of age and cystic periventricular leukomalacia commonly develops after the neonatal period, serial scanning is mandatory to ensure diagnostic accuracy for both periventricular haemorrhage and leukomalacia.