We know that many cerebral lesions are of circulatory origin and it is now important to study cerebral hemodynamics by pulsed and color Doppler ultrasonography. The revolution in the imaging of vascular physiology, the diagnosis, and the prognostic evaluation of vascular disease are not based on morphological sonographic studies but on the Doppler techniques that can display cerebral vessels in the neonate. The results of the hemodynamic investigation in 491 newborns aged from 32 weeks of gestation to 9 months by means of pulsed and color Doppler are reported. Normal values of the resistive index, peak systolic, end-diastolic, and time-averaged velocities in seven different vessels are determined. Some pathological examples are presented. Doppler techniques play a major role in the diagnosis, follow-up, and management of brain damage, whether ischemo-hemorrhagic, infectious, or developmental or tumoral, and of pericerebral collections.