There is a significant risk of disease recurrence in patients with nondiarrheal (D−) hemolytic uremic syndrome (HUS) undergoing renal transplantation. Recent studies have found that approximately 20% of sporadic cases of HUS have mutations in the gene for the complement regulatory protein factor H. The authors report on 2 families, in each of which a family member initially presented with sporadic HUS and subsequently received a live-related renal transplant, one from a sibling and the other from the father. Subsequently, both recipients suffered recurrent HUS in the allograft, and both donors had HUS within a year of the transplant. Neither family has a factor H mutation. This report underlines the risk of disease recurrence in recipients associated with live-related renal transplantation in HUS and also suggests that the donors may be at risk. Am J Kidney Dis 40:E22. © 2002 by the National Kidney Foundation, Inc.