A total of ninety patients (52men and 38women) were included in the study. Forty five patients developed septic complication during ICU stay (sepsis group). Forty five patients were critically ill without evidence of infectious organism (SIRS group). At admission, Patients data include clinical status; SOFA score; central venous pressure; laboratory analysis and arterial blood gas analysis were measured. Routine cultures were obtained. The attending physician evaluated the patients for sepsis, severe sepsis, or septic shock as long as their stay in ICU. A serum level of TNF-a and SOFA score was monitored.