Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominantly inherited disorder characterized by cutaneous and mucosal telangiectasias, epistaxis and arteriovenous malformations in lung, liver, central nervous system, and gastrointestinal tract. Mutations in the genes for endoglin (ENG) and for activin A receptor type II-like kinase 1 (ALK-1) have been identified to be associated with HHT. Intrahepatic manifestation in HHT might lead to the requirement of liver transplantation. We report here on 6 liver transplanted patients and 2 who were scheduled for liver transplantation due to intrahepatic HHT, in whom both genes were sequenced. Mutation analysis revealed in all patients the presence of mutations in ALK-1. In conclusion, these results are of possible prognostic value concerning the need of liver transplantation in HHT patients.