1. All cardiac surgery pts developed SIRS, during the first 12 postoperative hours, which lasted few hours. 2. Sepsis developed in critically ill cardiac surgery pts with severe perioperative complications. 3. Septic pts had significantly higher bypass time and aortic-cross clamp time, and received more blood transfusion and inotropic agents perioperatively compared with pts with SIRS (p<0.0001) 4. Staphylococcus epidermidis was the predominant pathogen isolated (48.1%). 5. Mortality rate was 1.1% in SIRS group and (31.7%) in septic pts.