Sixty-one instances of congenital anomalies identified prenatally by ultrasound were reviewed to determine whether autopsy provided important additional information. An important finding was defined as one which would affect: 1) genetic counseling; 2) diagnosis of a syndrome; 3) determination of etiology or pathogenetic mechanism of the anomaly; or 4) interpretation of severity of the anomalies. In 28 cases (46%), post-mortem examination provided such information. All of these infants had multiple anomalies; correlations with oligohydramnios and poor fetal outcome were noted. Autopsy provided no additional meaningful information in 30 cases (49%), the majority (77%) of whom had isolated anomalies. In 3 cases (5%), due to tissue autolysis, autopsy provided less information than the previous ultrasound. Although most fetal anomalies are readily diagnosed by ultrasound, we found that post-mortem examination is still necessary: 1) to confirm a prenatal diagnosis; 2) to delineate multiple anomalies; 3) when the ultrasound examination is limited by oligohydramnios; and 4) to obtain tissue for microscopic examination, cytogenetic and biochemical analysis, if these studies have not been performed prenatally.