The German Clinical Trials Register (DRKS) is the German WHO primary registry. It is competent for the registration of all patient-oriented clinical trials conducted in Germany. The aim of the registry is to offer the public a complete, up-to-date overview of clinical trials in Germany. The DRKS is not only a source of information for patients. It also supports the expert audience in the planning of clinical trials e.g. by helping to avoid redundant trials.