Sonographic examinations were performed on 13 patients whose fetuses had the following congenital malformations: anencephaly (4 cases), hydrocephaly (4), obstruction of the renal excretory system (3), iniencephaly (1), and sacrococcygeal teratoma (1). In 7 cases the initial diagnosis was made by sonography, in 6 cases by radiography. Sonography was valuable a) in the detection of discrepant growth between fetal chest and head and b) in the recognition of fetal soft tissue abnormalities. It is concluded that sonography is a valuable aid in the diagnosis of congenital fetal anomalies.