BACKGROUND: Patients with chronic renal failure traditionally have been recognized as being at risk for perioperative bleeding diathesis. However, there has been a few reports that chronic renal failure patients showed a hypercoagulability. The purpose of this study was to assess blood coagulation profiles in patients with chronic renal failure using a thromboelastography. METHODS: Thirty patients (ASA physical status, 2 and 3) with chronic renal failure (experimental group), were scheduled to get presenting for an arteriovenous fistula formation, and 30 patients with normal renal function (control group) were randomly selected. Blood sampling for a thromboelastography was performed prior to induction of anesthesia. A thromboelastography was analyzed by measuring R time, K time, maximum amplitude (MA), alpha degree, and TEG index. Laboratory tests including serum blood urea nitrogen, creatinine, hematologic data (hemoglobin, hematocrit, platelet count), and coagulation data (PT, PT-INR, aPTT, BT) were also measured in all patients preoperatively. RESULTS: In the thromboelastographic indices, K time was significantly decreased and MA, alpha angle, and TEG index were significantly increased in patients with chronic renal failure (experimental group) compared with the control group (P<0.05). However, there were no significant differences of PT, PT-INR, aPTT, BT between the groups. CONCLUSIONS: Thromboelastographic data demonstrates a hypercoagulable state in patients with chronic renal failure. This finding suggests that traditional concern for bleeding diathesis in patients with chronic renal failure may require reassessment.