Sepsis and related complications are a challenge for intensive care medicine. Despite many advances in antibiotic therapy sepsis remains one of the most common diseases of patients in intensive care units and is designated as the main cause of death in critically ill patients. Persisting sepsis leads to impaired immunity, resulting in immunosuppression. Unspecific predictive signs complicate an early diagnosis; however, an early initiation of adequate therapy is of crucial importance for the prognosis. Scoring systems can be applied for the initial evaluation but are controversially discussed concerning the monitoring of disease progression and therapy as well as outcome prediction. Biomarkers are considered as a complementary approach.