In 1995, the results of two extensive prevalence studies on hospital-acquired infections were published. Both studies included a prevalence component for German intensive care units (ICUs), but provided very different infection rates. A comparison of the methods used revealed that the data from the ICUs included in the German section of EPIC (European Prevalence of Infection in Intensive Care), reflected the situation in the ICUs of large hospitals. The situation in ICUs with fewer than 600 beds was quite different, and led to the lower overall rate of infection as seen in the NIDEP (Nosocomial Infections in Germany-Surveillance and Prevention) study. Additionally, the NIDEP data permitted the calculation of device-associated, device-day, infection rates for urinary tract infections, pneumonia and bacteraemia. The differences between the ICUs in the two hospital groups were mainly due to a lower use of patient devices with regard to urinary catheters, central venous lines and respiratory ventilators.