SummaryEstimated cerebral blood flow (eCBF) was measured sequentially in seven term infants with evidence of hypoxic-ischemic encephalopathy (HIE) and compared with that of normal-term infants. The eCBF was determined by a noninvasive method involving brief bilateral jugular venous occlusion with simultaneous measurement of occipitofrontal circumference. There was a significant decrease in eCBF on day 2 (30 ± 4 ml/min/100 g brain weight) and on day 4 (36 ± 5 ml/min/100 g brain weight) compared with control values (56 ± 4 ml/min/100 g brain weight; 54 ± 4 ml/min/100 g brain weight) (P< 0.01). The alveolar CO2was significantly lower on days 2 and 4 in the HIE group (P< 0.001), and these values increased to control values by day 6. There was no significant correlation between estimated cerebral blood flow and alveolar CO2in infants with HIE. We conclude that term infants with evidence of hypoxic-ischemic encephalopathy demonstrate lowered eCBF in the first 4 days of life.