We present the autopsy report of a liveborn triploid female, born after 36 weeks of gestation, who died at the age of 20 hours. External features were diagnostic: fetal hypoplasia, hypertelorism, microstomia, micro-and retrognathia, preauricular skin tag, low-set ears, and 3-4 syndactylia. All internal organs were hypoplastic. There were atrial and ventricular septal defects. Adrenals and kidneys were fused, the gallbladder was absent, and ovarian hilum cell were found to be hyperplastic. Triploidy, 69xxx, was confirmed cytogenetically. The placenta was hypoplastic and, microscopically, revealed a peculiar type of immaturity, so-called hydatidiform villous hypoplasia, findings which have not been previously reported. We suggest that the generalized fetal and placental hypoplasia and the severe hypoplasia of all internal organs are caused by a proliferative deficiency of the triploid cells. In addition, the nuclear DNA content was determined by cytophotometrically from placental stromal cells and was found to be about 50% above the normal diploid DNA value; i.e., a triploid DNA value was confirmed.