Many experimental and clinical findings indicate a disimmune pathogenesis of infertility associated with endometriosis. The most important modifications of cell-mediated immunity in endometriosis concern macrophage activity, increased both quantitatively and qualitatively. Peritoneal macrophages (PM) acquire the ability of producing lytic enzymes, that would be able to enhancing and stimulating implantation and proliferation of endometrial cells in peritoneal cavity. In these last years many experimental and clinical demonstrations have showed an immunosuppressive action of Danazol similar to corticosteroids. The Authors report their study on a comparison among Danazol 600 mg/daily for 3 months plus a local immunosuppressive treatment combined with superovulation and IPI, Danazol for 3 months plus superovulation and IPI and, as a control group, superovulation and IPI.