The treatment with Luteinizing hormone-releasing hormone, (LHRH) agonists provides proven pain relief in 80 -90% of women with documented endometriosis. However, after the end of the therapy symptoms recur. The administration of LHRH agonists for 6 months as an adjuvant measure after surgery has been shown to extend the pain-free interval. The addition of immediate add-back therapy does not reduce the efficacy of LHRH agonists, while preventing loss of bone substance and alleviating the symptoms of hypoestrogenism. Thus, in combination with add-back therapy LHRH agonists should be considered a first-line treatment for relief of endometriosis related pain. If IVF is planned in patients with endometriosis, they should receive 3-6 months of therapy with LHRH agonists prior to starting the stimulation, as pregnancy rates are significantly increased by this treatment modality. LHRH antagonists deserve further consideration because of their immediate onset of action which avoids the flare up effect in the therapy of endometriosis. Still more important is the possibility of titrating estrogen levels with appropriate doses of antagonist, long-term treatment without add-back therapy might be possible with the antagonists of LHRH.