There is an obvious need for teamwork between different specialists on the diagnosis and treatment of patients in an intensive care unit. The infectious disease specialist must contribute by establishing definite and quick diagnosis of infections and by employing an adequate and sensible antibiotic policy for successful treatment. The local microbiological flora should be kept at an acceptable level of resistance to antibiotics, and preventive measures should be chosen carefully. To achieve this goal, extensive knowledge on antibiotics and microbial epidemiology is essential.