Today GnRH-Analogues are the most effective substances for the regression of endometriosis and endometriosis related complaints. In combination with add-back medication the treatment is effective with only few tolerable side effects. The different types of GnRH-Analogues are equally effective, but depot preparation have the best compliance. The tailored application of GnRH-Analogues preoperatively, postoperatively or instead of surgery is dependent on the individual situation of the patient and dependent on the proliferative activity, localisation, type and stage of the disease.