Ten cases of prenatal diagnosis of isolated hypospadias are presented, six of them in the second trimester. The echographical basis for the suspected diagnosis of hypospadias are: anomalous distal morphology of the penis, small lateral folds (dermal remains of the prepuce), small penis with ventral incurving and anomalous urinary stream. The embryogenesis and the clinical utility of prenatal study of the genitals of the fetus, not only to determine the sex, but also to detect anomalies, are discussed.