Atypical hemolytic uremic syndrome is often associated with mutations in genes encoding complement regulatory proteins and secondary disorders of complement regulation. Progression to kidney failure and recurrence with graft loss after kidney transplantation are frequent. The most common mutation is in the gene encoding complement factor H. Combined liver-kidney transplantation may correct this complement abnormality and prevent recurrence when the defect involves genes encoding circulating proteins that are synthesized in the liver, such as factor H or I. Good outcomes have been reported when surgery is associated with intensified plasma therapy. A consensus conference to establish treatment guidelines for atypical hemolytic uremic syndrome was held in Bergamo in December 2007. The recommendations in this article are the result of combined clinical experience, shared research expertise, and a review of the literature and registry information. This statement defines groups in which isolated kidney transplantation is extremely unlikely to be successful and a combined liver-kidney transplant is recommended and also defines those for whom kidney transplant remains a viable option. Although combined liver-kidney or isolated liver transplantation is the preferred therapeutic option in many cases, the gravity of risk associated with the procedure has not been eliminated completely, and assessment of risk and benefit requires careful and individual attention.