Sacrococcygeal teratoma (SCT) is a rare subset of germ cell neoplasm and occurs in approximately 1 in 35,000 live births. Most SCTs are benign, but about 20% are malignant. They originate from totipotent cells from Hansen's node or primitive germ cells, but the exact etiology remains uncertain. Antenatal diagnosis of SCT can be made by ultrasound. The fetus with SCT remains at high risk for perinatal complications and death. Perinatal mortality and morbidity are most strongly related to high-output cardiac failure because of arteriovenous shunting within the tumor, subsequent fetal hydrops, polyhydramnios, and preterm delivery. Recently we have experienced a case of immature SCT with hydrops and polyhydrmnios diagnosed by prenatal ultrasonography at 21+5 weeks, resulted in stillbirth. We describe this case with a brief review of the literature.