Background. Low-molecular-weight heparin (LMWH) is recommended for venous thrombosis prophylaxis. There are several lines of evidence that heparins exhibit anti-inflammatory properties in addition to their anticoagulant activity. Therefore, we decided to estimate the concentrations of C-reactive protein (CRP) and haptoglobin, as acute-phase proteins, in the blood serum of patients who underwent total abdominal hysterectomy with and without the LMWH administration. Method. Forty-two women were studied, including 26 patients treated with enoxaparin and a group of 16 women without thrombosis prophylaxis. Haptoglobin and CRP concentrations were measured in serum samples obtained before the operation and also 8, 24, 48, 72, 96, and 192 hr after surgery. Results. Serum CRP level measured 8 hr after the operation was significantly higher in the group without thrombosis prophylaxis, however, no statistically significant differences in the concentration of CRP between studied groups in the other time periods were found. There were no statistically significant differences in serum haptoglobin levels between the groups of patients in all time periods. Conclusion. Administration of low-molecular-weight heparin may affect CRP production, however, further studies are still needed in order to clarify the exact immunosuppressive action of heparins.