According to § 23 paragraph 4 of the German Infection Prevention Act (IfSG; July 2011), hospitals and clinics for ambulatory surgery are obliged to establish a continuous monitoring system of antibiotic consumption. This is aimed at contributing to an optimization of antibiotic prescription practices in order to confine the development and spread of resistant pathogens. The general requirements (restricted to hospitals) on the method and extent of data collection are provided by the national public health institution after discussion with representatives of various professional societies (Robert Koch-Institut, Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 59, 2013). The article aims to clarify these specifications and to provide background details. In agreement with national and European surveillance systems, the Anatomical Therapeutic Chemical (ATC)/Defined Daily Dose (DDD) classification system recommended by the WHO should be used as reference standard. Antibiotic consumption should be expressed as the number of DDDs per 100 patient days and per 100 admissions. The categories of antimicrobials and hospital organizational units to be monitored and the time intervals in which analyses should be conducted are determined. Furthermore, various approaches of data assessment are described.