Endometriosis is one of the frequent gynecological diseases in premenopausal women. The clinical diagnostics is difficult because symptoms of endometriosis are variable. The surgical removal of endometriosis is the primary therapeutic aim. Medical treatment plays a very important role in the therapy of this chronic disease. A symptomatic therapy by analgetics should be combined with a hormonal treatment. The use of oral contraceptives in extended cycle or long-term use is effective against endometriosis associated pain. Progestogens, especially dienogest, which is licensed for endometriosis treatment and good investigated, are very effective and also available for long-term use. GnRH-analogues are effective for a short-term treatment (duration of 3 months). The long-term treatment with GnRH-analogues should only be used in selected cases and in combination with an add back therapy. Treatment of endometriosis should be planned individually for each patient, dependent on stage, localization and activity of endometriosis and further family planning. By the combination of hormonal and operative treatment possibilities a maximum period free of pain or recurrence of endometriosis can be reached.