Two cases of Cornelia de Lange syndrome associated with infantile haemangioendothelioma of the liver and Wilms' tumour are reported. The patients showed the characteristic facies of the Cornelia de Lange syndrome, with synophrys, long curly eyelashes and small upturned nose, and physical features, including generalized hirsutism, monodactyly, syndactyly and clinodactyly. Post-mortem examination revealed annular pancreas, patency of the foramen ovale, duodenal atresia and evidence of cytomegalic infection. The cases are reported to document a possible association between malformations and neoplasms in this syndrome.