In the last few years, there has been a growing interest in the study of complement, fueleld mainly by the design of complement modulators, especially the C5-blocker eculizumab. The latter has significantly improved the prognosis of some nephropathies, such as the atypical hemolytic uremic syndrome. This breakthrough is a perfect example of fundamental translational research leading to clinical applications for patients. Currently, new molecules are being developed and some of them have already demonstrated clinical efficacy, such as avacopan (C5aR blocker) in ANCA vasculitis. As for kidney transplantation, complement modulators may lead to a new perspective in the treatment of some complications, such as humoral rejection. However, complement modulators carry the side effects, especially the infectious, and high costs.