Serial Doppler studies of the anterior cerebral artery were performed on 50 healthy term infants in the first 5 days of life. This study aims to establish a normative database for cerebral Doppler measurements in infants born appropriate for gestational age (AGA) and to compare them with those born small for gestational age (SGA). The difference between SGA and AGA infants was documented. In AGA infants, the Pourcelot's resistance index (PI) decreased over the first 5 days, while both the peak systolic flow velocity and end diastolic flow velocity increased. In SGA infants, the PI was significantly lower in the first 24 h of life. This was accounted for by an increase in the end diastolic flow velocity which may be a continuation of the intrauterine situation. The significance of the difference is discussed.