We describe a sporadic case of lethal prenatal onset infantile cortical hyperostosis (Caffey disease), which resulted in early postnatal death at 30 weeks gestation. The mother presented with antepartum haemorrhage and preterm labour. She was found to have polyhydramnios. The infant showed extensive symmetrical diaphyseal subperiosteal cortical thickening throughout the skeleton with short extremities. Hepatomegaly and lung hypoplasia were present. Currently, in the absence of a specific marker, diagnostic ultrasound offers the only prospect of prenatal diagnosis. This diagnosis should be considered in infants with short angulated long bones, where the diaphyses are irregular and echodense, and where there is no sign of fractures.