Since its approval in the 1950s, warfarin has been the most often prescribed anticoagulant, with attendant risks of bleeding. Brodsky et al. describe another potential complication of warfarin therapy. Warfarin-related nephropathy (WRN) has been described in patients with chronic kidney disease and appears to accelerate the rate of progression and increase the risk of death. The interactions between warfarin and chronic kidney disease are complex, and the recognition of the potential complications is expanding. © 2011 International Society of Nephrology.