Fifty-five children with congenital eventration of the diaphragm were operated upon in a single tertiary-care children's hospital during the 45-year period from 1948 to 1992. The study was divided into three periods: 1948-1962, 1963-1977, 1978-1992. There were 14 patients in the first group, 26 in the second, and 15 in the third. Children later in the series presented earlier and with more acute symptoms. Mortality was related to severe pulmonary hypoplasia and associated anomalies, especially chromosomal defects: 14% during the first period, 27% during the second, and 7% during the third.