The German self-governing bodies have concluded an agreement about ambulant operations and procedures which replaces the inpatient health care situation. It came into force on January 1, 2004. The published catalogue contains specific treatment procedures which define more clearly some problems that occur between the provision of outpatient and inpatient services in the German health care system. Clinical physicians and practising specialists now have equal rights to provide and to charge for the ambulant services that are included in this agreement. These conditions will play a role in the daily routine of hospitals and will influence treatment patterns. A comprehensive knowledge of the basic principles is essential. In the present article, the compulsory agreement and some resulting consequences are elucidated with special relevance to gastroenterology.