Warfarin is a well-established cause of gross hematuria. However, impaired kidney function does not occur except in the rare instance of severe blood loss or clot formation that obstructs the urinary tract. It has been recently described an entity called warfarin-related nephropathy, in which acute kidney injury is caused by glomerular hemorrhage and renal tubular obstruction by red blood cell casts. We report a patient under warfarin treatment with chronic kidney disease, macroscopic hematuria and acute kidney injury. A renal biopsy showed massive occlusion of renal tubules by red blood cells and casts. The possible relationship of the warfarin therapy, intratubular hemorrhage and acute kidney injury is discussed.