The aim of the study was to determine the incidence of electrographic seizure activity in a prospective cohort of preterm infants and relate it to the presence of cerebral injury. Infants born <30-wk gestation received a median 74 h of continuous 2-channel EEG with amplitude-integrated EEG monitoring in the first week of life. Infants were classified in the abnormal outcome group if they died in the neonatal period and/or had grades 3-4 intraventricular hemorrhage and/or moderate or severe abnormalities on cerebral MRI. Seizures were defined as rhythmic spike and/or wave activity lasting at least 10 s on the raw EEG trace. Eleven of 51 infants monitored had electrographic seizures. These infants were more premature had lower birth weights and a greater proportion had abnormal outcomes. In four infants, seizures preceded ultrasound findings of grades 3-4 intraventricular hemorrhage. Three of the four infants with seizures and concurrent physiologic recordings displayed concurrent rises in heart rate and one showed a fall in respiratory rate. In conclusion, electrographic seizures were more likely to occur in the sicker and more premature infants with abnormal outcomes. Seizures detected on continuous amplitude-integrated EEG monitoring with the raw EEG were associated with poor outcome.