Following the incidental diagnosis of triventricular hydrocephalus in a fetus 34 weeks after the mother's last menstrual period, during an uneventful pregnancy, 1.5-T brain magnetic resonance (MR) was carried out. A subependymal hemorrhage, which had not been revealed by transabdominal ultrasound, was found; this finding was confirmed by neonatal brain ultrasound and MR. Fetal MR allowed identification of the hemorrhage as the cause of the hydrocephalus and also established its time of occurrence. Unexplained hydrocephalus should be included among the indications for fetal MR.