The findings of cranial sonography performed before and during extracorporeal membrane oxygenation (ECMO) in 50 near-term infants and CT findings after ECMO in 18 of those patients are reported. Hemorrhage is uncommon in patients being considered for ECMO: subependymal hemorrhage was seen in one case and subependymal cyst possibly due to in utero hemorrhage was seen in five cases. Hypoxic ischemic ischemic injury is more common: severe cerebral edema was seen in two cases, occipital hemorrhagic infarct in one case, and mild cerebral edema in 17 cases. During ECMO, sonograms showed that the hemorrhage in patients with small subependymal hemorrhage or cyst before ECMO did not extend while on ECMO. Typical germinal matrix/intraventricular hemorrhage was seen uncommonly (three cases). Unusual parenchymal hemorrhage did occur. Hypoxic ischemic brain injury was more common: parenchymal hemorrhage was seen in three cases, severe cerebral edema in three cases, and infarction in three cases. Hypoxic ischemic brain injury probably occurs before ECMO, with a delay in visualization. CT after ECMO detected additional abnormalities, particularly peripheral areas of hemorrhage and infarction not visible on sonograms, and is now being performed on all patients. More emphasis should be placed on better screening of infants being considered for ECMO treatment to identify irreversible anoxic brain injury, not just hemorrhage.