Background and objectives: A male infant with a family history of thrombotic microangiopathy developed atypical hemolytic uremic syndrome (aHUS).Design, setting, participants, & measurements: Case report. Results: Genetic analysis demonstrated a heterozygous mutation (S1191L) of CFH, the gene coding complement factor H (CFH). The child suffered many episodes of HUS, each treated with plasma exchange. In time, despite initiation of a prophylactic regimen of plasma exchange, his renal function declined significantly. At the age of 4 yr he received a (split liver) combined liver-kidney transplant (LKT) with preoperative plasma exchange and enoxaparin anticoagulation. Initial function of both grafts was excellent and is maintained for nearly 2 yr.Conclusions: This report adds to the small but growing number of individuals in whom LKT has provided a favorable outcome for aHUS associated with CFH mutation, expands the technique of using a split liver graft, and describes the unique histologic features of subclinical liver disease in HUS.