Since the introduction of neonatal extracorporeal membrane oxygenation (ECMO) in Canada, the authors have treated three infants with congenital diaphragmatic hernia (CDH) who had serious congenital cardiac anomalies (among 26 infants with CDH treated with ECMO). To determine the incidence of and outcome for infants with combined lesions who received ECMO, 19 years' data (April 1973 to October 1992) from the Extracorporeal Life Support Organization (ELSO) registry were reviewed. Seventeen infants with combined cardiac and diaphragmatic lesions were registered as receiving ECMO in the United States or Canada. Thus, the incidence of combined cardiac and diaphragmatic lesions was 2.5 per thousand neonates (17 of 6,295) receiving ECMO and 13 per thousand neonates (17 of 1,318) receiving ECMO for CDH. Five (29.4%) of the 17 infants survived. A congenital cardiac lesion may not be an absolute contraindication to ECMO in infants with CDH. Decisions to cannulate for ECMO should be based on the potential outcome of the underlying cardiac defect.