The current economic climate in the health care system makes it necessary to contain costs while maintaining a high-quality standard in the treatment of critically ill patients. Hospitals and ICUs are being more and more compared to industrial production sites. Physicians have a considerable influence on both medical performance and costs. For a better operative controlling and management of ICUs under these new conditions cost-benefit analyses, effective resource utilization and the implementation of a quality control concept are required. To create a reliable data base, the interdisciplinary quality assessment research group of the German interdisciplinary society for intensive care medicine (DIVI) carried out a multicentre evaluation from November 1999 to February 2000 in German ICUs. In a prospective cohort study of all 1368 German hospitals having ICU units with 21,918 ICU beds were evaluated by a standardized 53-item questionnaire for their structural data, technical assessment and quality control concepts. If not indicated otherwise, numbers are given as mean ± SD. 400 data sheets returned. Only complete data sheets where used for analysis resulting in the inclusion of 349 ICUs (25.5%). Data of 353,503 patients treated in 349 ICUs per year were available for data evaluation. The mean number of patients per ICU was 1032 (± 887). The number of days with artificial ventilation were 361,071 representing 88,375 patients which corresponds to an average of 1097 (± 1778) ventilation days per ICU. The total number of ICU treatment days was 1,071,112 corresponding to 3353 (± 7542) days per unit. Concerning ICU personnel the data showed that 3.4 (± 3.3) physicians and 22.6 (± 15.9) nurses are working on the average ICU in Germany. Regarding the availability of technical equipment (echocardiography, lab units on the ICU, arterial blood gas analysis, Swan catheter, ICP monitoring, cardiac pacing, renal replacement therapy, IABP and ECMO) there was no statistical difference between day and night services. For quality assessment mortality and morbidity conferences are held in 93 centres (27%). Worst cases are analyzed in 311 centres (89%). Staff education is institutionalized in 333 (95%) ICU units. Microbiological monitoring by a microbiologist is standard procedure in 91 centres (26 %). Based on this reliable data material a current quality assessment concept can be developed to optimize both cost strategies and medical structure.