Data are presented on 17 children who received extracorporeal membrane oxygenation (ECMO) in the neonatal period for persistent pulmonary hypertension (PPHN). These children are being followed as part of a larger program of follow-up research on children who have been treated for PPHN with several treatment methods. On intelligence testing at ages 5 to 8 years, these 17 children had unusual patterns of results. A higher-than-predicted percentage of the ECMO survivors had discrepancies between their Verbal and Performance IQ and a much-higher-than-predicted percentage had areas of unusual strength or weakness on their IQ subtest scores. Also, there was a significant correlation between the amount of time a child received ECMO and the child's Performance IQ: the longer the child received ECMO, the higher the Performance IQ. While findings of unusual weaknesses or deficits on intelligence testing at school age in children who have been severely ill in the neonatal period are not unusual, findings of high scores and areas of strength are not easily explained, particularly when these findings seem to relate to an invasive treatment like ECMO. Similar findings have been reported in two other small studies, which suggest that the impact of ECMO on the developing infant brain may not be purely detrimental.