The significance of nosocomial infections is increasing. The reasons for this are a higher concentration of problematic patients in hospitals due to the increasing number of outpatient surgeries, the increase of invasive therapeutic and diagnostic procedures, the growing share of immunodeficient patients as well as the increase in antibiotic-resistant and multiresistant pathogenic organisms. Basic changes in the medical system call for a systematic discussion about directed quality management. Surveillance, i.e., the systematic registration and evaluation of occurred diseases as well as the feedback to the personnel in charge is very important in this context, particularly when complemented by comprehensive hygienic measures. The growing significance of hospital infections increasingly triggered by multiresistant pathogenic organisms emphasizes the importance of general prevention. Each hospital has to determine which surveillance methods for the registration of nosocomial infections and multiresistant pathogenic organisms are the most appropriate under their respective conditions. To get a first idea of possible problem areas, prevalence studies are very suitable for the start before moving on to well-directed incidence studies in certain wards and for certain kinds of infection.