Lilian M Pereira Palma,1 Craig B Langman2  1Pediatric Nephrology, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil; 2The Feinberg School of Medicine, Northwestern University, and the Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA Abstract: The biology of atypical hemolytic uremic syndrome has been shown to involve inability to limit activation of the alternative complement pathway, with subsequent damage to systemic endothelial beds and the vasculature, resulting in the prototypic findings of a thrombotic microangiopathy. Central to this process is the formation of the terminal membrane attack complex C5b-9. Recently, application of a monoclonal antibody that specifically binds to C5, eculizumab, became available to treat patients with atypical hemolytic uremic syndrome, replacing plasma exchange or infusion as primary therapy. This review focuses on the evidence, based on published clinical trials, case series, and case reports, on the efficacy and safety of this approach. Keywords: acute kidney injury, ESRD, thrombotic microangiopathy, kidney, alternative complement pathway, complement blockade