Two infants with diffuse neonatal hemangiomatosis are presented. One infant developed thrombocytopenia and bleeding while the other infant with more widely diffuse lesions succumbed to extensive central nervous system involvement. Steroid therapy caused no obvious alteration in either of the patient's course. The vascular lesion in this disease is possibly congenital absence of vessel wall pericytes. Six previous cases of diffuse neonatal hemangiomatosis are briefly reviewed in relation to the sites of the lesions, cause of death and malignant potential.