Objective To determine the effect of ulinastatin on perioperative inflammatory response to coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). Methods Forty patients undergoing CABG with CPB were randomly divided into 2 groups: a ulinastatin group (1.5×10~4 U/kg before CPB, n=20) and a control group (n=20). The inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-10 and neutrophil elastase (NE) were measured before the anesthesia (T1), 1 h after the start of CPB (T2), 1 h after weaning of CPB (T3), and 24 h after weaning of CPB (T4). The postoperative organ dysfunction in the 2 groups was noted.Results The concentration of TNF-α, IL-6, IL-10, and NE at T2,T3, and T4 and increased more significantly than that at T1 in the 2 groups(P<0.05). The concentration of TNF-α, IL-6 and NE at T2, T3, and T4 in the ulinastatin group decreased more significantly than that in the control group (P<0.05), and IL-10 in the ulinastatin group increased at the same time. The postoperative complications of pneumonia, kidney and central nervous system in the ulinastatin group decreased more significantly than that in the control group (P<0.05). There was no significant difference in the postoperative cardio or liver complications and hours in the ICU between the 2 groups.Conclusion Administration of ulinastatin before CPB can decrease the inflammatory response and complication during CABG.