Significant bleeding during cardiac surgery, enough to cause re-exploration and/or blood transfusion, increases morbidity and mortality. Bleeding after cardiopulmonary bypass is related to multiple factors: endothelial dysfunction, thrombocytopenia, dilution coagulopathy. Hyperfibrinolysis is one of the important contributors to increased bleeding. To compare the effect of aprotinin with the effect of lysine analogues (aminomethylbenzoic acid and epsilon aminocaproic acid) examined 63 patients were divided into three equal groups depending on the product used for the prevention of activation of fibrinolysis. Data from rotational thromboelastometry measurements (Rotem Gamma Pentapharm, Germany), blood loss and transfusion were collected. The results confirm that used in the study antifibrinolytics: the lysine analogues aminomethylbenzoic acid and epsilon aminocaproic acid prevent hyperfibrinolysis after cardiopulmonary bypass as well as aprotinin.