Persistent pulmonary hypertension of the newborn and its attendant hypoxemia may place the infant at high risk for hypoxic-ischemic injury. In 19 infants with persistent pulmonary hypertension of the newborn, 16 of whom suffered intrapartum asphyxia, we evaluated a series of electroencephalograms (EEGs) for evidence of major focal cerebral injury, ie, persistent voltage attenuation and/or focal electrical-seizure activity. Of the 15 infants (78.9%) with such EEG findings, nine infants (47% of the total population) had cerebral infarction documented by cranial sonograms, computed tomographic scans, or autopsy findings. In eight (89%) of the nine infants with infarction, electrical seizures were noted during periods of muscle paralysis. We recommend (1) the use of electroencephalography in this population, particularly during periods of muscle paralysis, to detect underlying cerebrovascular lesions and (2) the use of cranial computed tomography if persistent, focal EEG abnormalities are noted.