To evaluate coagulation status after cardiopulmonary bypass and its relation to renal function, thrombin-antithrombin III complex and prothrombin fragment 1+2 were measured as thrombotic markers in 46 patients undergoing coronary artery bypass grafting. Postoperative serum creatinine values exceeded 20 mg·L−1 in 12 patients, indicating compromised renal function; there was a statistically significant increase in the postoperative levels of thrombotic markers in these patients. These data indicate that patients with renal dysfunction after cardiopulmonary bypass have a thrombotic tendency. Anticoagulant treatment is recommended in such patients.