The reported mortality for prenatally detected congenital diaphragmatic hernia is high. We retrospectively reviewed 18 cases of congenital diaphragmatic hernia diagnosed prenatally in our hospital and analyzed several high-risk factors adversely affecting outcome. The diagnosis before 32 weeks gestation is associated with high mortality than in cases detected later. Polyhydramnios and underdevelopment of left-side cardiac structures were found to be helpful prognostic factors. These should be taken into account when the management of these cases is planed.