A population of healthy, full-term newborn infants was studied in order to obtain documentation of the prevalence of intracranial hemorrhage. Cerebral ultrasonography was performed within 72 hours of birth on 505 healthy newborn infants, 37 weeks of gestation or greater. Sonographic abnormalities were detected in 23 (4.6%) neonates. Bilateral subependymal germinal matrix hemorrhage occurred in 14 and unilateral hemorrhage in five infants. Other abnormalities detected included agenesis of the corpus callosum in two infants, a cyst involving the subependymal germinal matrix in one (presumably the result of a previous subependymal hemorrhage), and mild ventricular dilation of unknown etiology in one. Newborns with subependymal hemorrhage were compared with newborns without hemorrhage in order to determine whether any significant differences existed between the two populations. No significant differences existed between infants with and without subependymal hemorrhage with regard to gender, obstetrical presentation, use of forceps, birth trauma, Apgar scores, need for resuscitation, maternal age and parity, and neonatal clinical problems. Infants with subependymal hemorrhage were of significantly lower gestational age and birth weight; the overall difference in weight was attributable to lower weight in female infants with subependymal hemorrhage. Significantly more infants with subependymal hemorrhage were small for gestational age, vaginally delivered, and black.