The importance of antibiotic consumption and bacterial resistance analysis is unquestionable. Although the WHO has been recommending the use of ATC/DDD method for the analysis of drug utilization for about 20 years, only limited numbers of publications are available considering the antibiotic consumption of in-patients. In the present study--with the help of the mentioned method--we analysed the utilization of antibiotics in 5 clinical departments. We also investigated the connection between antibiotic consumption, bacterial resistance and enterococcal sepsis at the haematologic department. We could follow the successful impact of the implementation of the new guideline.