43 term infants with clinical neurological manifestations of intrapartum asphyxia and who survived for more than 2 days were studied sequentially, while in hospital, with doppler ultrasound examination of the anterior cerebral arteries. 36 survivors with post-asphyxial encephalopathy were followed up for a median of 18 months and none who had had normal doppler measurements (defined by results in 49 non-asphyxiated babies) became seriously handicapped. Of the 18 infants with abnormal waveforms 12 had an adverse outcome (death or handicap). In the asphyxiated infants, doppler examination predicted outcome with an accuracy of 86%. The prediction of adverse outcome by abnormal doppler showed a sensitivity of 100% and a specificity of 81%. All abnormal results had occurred by 62 hours from birth.