This study was performed to evaluate the effects of Exocorpol and Haptoglobin on hemolysis during ECC. We measured free hemoglobin (F-Hb) and free haptoglobin (F-Hp) at pre- and post-ECC. Patients were divided four groups: Group C, 5 patients undergoing no treatment; Group Ex, 5 patients undergoing treatment of Exocorpol; Group Hp, 5 patients undergoing treatment of Haptoglobin; Group Ex + Hp, 5 patients undergoing treatment of Exocorpol and Haptoglobin. F-Hb of pre- and post-ECC in four groups were 0 mg/dl: 85 mg/dl (Group C, p < 0.01), 0 mg/dl: 2 mg/dl (Group Ex, NS), 0 mg/dl: 1 mg/dl (Group Hp, NS), 0 mg/dl: 0 mg/dl (group Ex + Hp, NS). F-Hp of pre- and post-ECC in four groups were 143 mg/dl: 9 mg/dl (Group C, p < 0.02), 133 mg/dl: 25 mg/dl (Group Ex, p < 0.05), 186 mg/dl: 195 mg/dl (Group Hp, NS), 66 mg/dl: 163 mg/dl (Group EX + Hp, p < 0.05). There was no significant difference in F-Hb and F-Hp of pre-ECC among four groups. F-Hb of post-ECC in Group C was significantly higher than that of Group Ex, Hp and Ex + Hp (p < 0.01), and F-Hp of post-ECC in Group Hp and Ex + Hp was significantly higher than that of Group C and Ex.(p < 0.01, p < 0.02). We concluded that Exocorpol and Haptoglobin were effective on hemolysis during ECC, and combination of these was more effective.