Background. The aim of this study is to compare the effects of sevoflurane and propofol on one lung ventilation (OLV) induced ischemia-reperfusion injury (IRI) by determining the blood gas, ischemia-modified albumin (IMA), and malonyldialdehyde (MDA). Material and Methods. Forty-four patients undergoing thoracic surgery with OLV were randomized in two groups (sevoflurane Group S, propofol Group P). Anesthesia was inducted with thiopental and was maintained with 1-2.5% of sevoflurane within the 40/60% of O-2/N2O mixture in Group S. In Group P anesthesia was inducted with propofol and was maintained with infusion of propofol and remifentanil. Hemodynamic records and blood samples were obtained before anesthesia induction (t(1)), 1 min before two lung ventilation (t(2)), 30 min after two lung ventilation (t(3)), and postoperative sixth hours (t(4)). Results. Heart rate at t(2) and t(3) in Group P was significantly lower than that in Group S. While there were no significant differences in terms of pH and pCO(2), pO(2) at t(2) and t(3) in Group S was significantly lower than that in Group P. IMA levels at t(4) in Group S were significantly lower than those in Group P. Conclusion. Sevoflurane may offer protection against IRI after OLV in thoracic surgery.