Few conditions associated with nonimmune hydrops fetalis have had a demonstrable causal relationship. Congenital heart disease is often said to be a cause of nonimmune hydrops fetalis and antenatal closure of the foramen ovale is the cardiac abnormality most frequently reported in association with hydrops. In order to examine the role of congenital heart disease in hydrops, and, in particular, that of antenatal closure of the foramen ovale, we reviewed all autopsy cases with hydrops fetalis over an 11 year period and compared cardiac anomalies with those of nonhydropic controls. The incidence of various congenital heart malformations was not significantly different among these groups, suggesting that factors in addition to cardiac anomalies must be considered in the pathogenesis of nonimmune hydrops fetalis.