An increased incidence of thromboembolic events has been described in women receiving systemic chemotherapy for breast cancer. The effect of anthracycline-based adjuvant chemotherapy regimens on fibrinolytic system markers of plasminogen activator inhibitor-1 (PAI-1) and thrombin activitable fibrinolysis inhibitor (TAFI) was investigated in patients with operable breast cancer. Twenty-four patients with operable breast cancer (median age, 54.5 years; range, 37-72 years) enrolled in our study. Stage I-II and stage IIIA cases received EC (Epirubicin 90 mg/m(2)/d1, I.V. and cyclophosphamide 600 mg/m(2)/d1, I.V.) and FEC (5-fluorouracil 500 mg/m(2)/d1, I.V., epirubicin 100 mg/m(2)/d1, I.V., and cyclophosphamide 500 mg/m(2)/d1, I.V.) as an adjuvant chemotherapy regimen, respectively. Each group consisted of 12 patients. Blood samples were obtained at baseline and just before the third cycle of EC and fourth cycle of FEC chemotherapy regimens. Plasma TAFI antigen and PAI-1 levels did not disclose any statistical difference between basal and postchemotherapy levels within each group and between two groups. Although postchemotherapy D-dimer levels were statistically higher in the FEC group than in the EC group, results in both groups were within normal ranges. More studies concerning the role of fibrinolytic system in breast cancer patients receiving chemotherapy, probably including cases with advanced stage and with different chemotherapy regimens and dose intensities, are needed.