Background: Little has been published regarding the association between perioperative stress response and clinical outcomes after off-pump coronary artery bypass surgery(OPCAB). We assessed the role of perioperative stress response in postoperative inflammatory complications(PIC) in patients undergoing OPCAB. Materials and Methods : The study cohort consisted of 100 patients who underwent elective OPCAB over a 5-month period. Blood samples were collected before surgery, immediate after surgery, 1, 2, 3, and 7days after surgery. Leukocyte,neutrophil,platelet,ESR,C-reactive protein,fibrinogen,cortisol,D-dimer,and FDP were measured at each time point, and the association of each parameter with PIC was assessed. PIC included postoperative pulmonary complications, atrial fibrillation, and wound infections. Results : PIC occurred in 30 patients at the median third postoperative day. Multivariate analysis revealed preoperative cortisol(p=0.024) and cortisol on the first postoperative day(p=0.001) were significantly associated with PIC. Intraoperative cortisol release was correlated with intraoperative hemodynamic changes, including pulmonary artery pressure, central venous pressure, and cardiac index. Conclusions: Patients with PIC after OPCAB have significantly increased preoperative cortisol and cortisol on the first postoperative day. Intraoperative cortisol release was significantly correlated with hemodynamic changes. The neurohormonal environment and inflammatory response during and after beating-heart surgery should be further explored.