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Patients with chronic renal failure frequently show complex hemostatic disorders, the most frequent being bleeding episodes. Hemorrhagic complications were more frequent and severe before dialysis procedures were available, but they still persist. Some of the spontaneous bleeding symptoms reported in uremic patients include cutaneous purpura, easy bruising, epistaxis, gingival bleeding, and hematuria. Less frequent but more severe bleeding complications affect internal organs. Gastrointestinal hemorrhage, associated with mucosal ulceration or telangiectasiae, was formerly the most common cause of death in this group of patients. Retroperitoneal hemorrhages have also been observed, often associated with other underlying conditions. Subdural hematoma after brain trauma, hypertension, or anticoagulation has been reported in 6% to 16% of hemodialysis patients. The prognosis of cerebrovascular hemorrhage is variable, with a high mortality rate (approximately 90%) in patients requiring emergency surgery. The observation that hemorrhages occurred in patients with normal and even elevated levels of coagulation factors suggested from the very beginning that bleeding in the uremic condition was related to a platelet dysfunction. The introduction of routine hemodialysis in the 1970s seemed to improve hemorrhagic symptoms, but did not completely correct the bleeding diathesis. Unfortunately, hemodialysis requires the use of anticoagulants to keep blood fluid in the circuits, and these anticoagulants were found to contribute to increased bleeding in uremic patients and to enhance the risk of gastric bleeding or subdural hematoma in …