Eleven patients with infertility of unknown cause and symptomatology suggestive of endometriosis were studied at the INPer. México from June 1, 1986 to December 15th, 1986. All these patients were subjected to a diagnostic laparoscopy, in 7/11 cases there were peritoneal lesions which were not classical of endometriosis in 2/11 there were typical endometriosical lesions and in the other 2/11 there was no evidence of lesion. Biopsies of nonpigmented endometriosis were obtained and in 7/11 endometriosis without hemosiderin were reported; in 2/11 endometriosis with hemosiderin and finally in 2/11 just an inflammatory process. We believe that the diagnosis of nonpigmented endometriosis must be suspected in all those patients with infertility of unknown cause who display endometriosic symptoms. When reorganizing nonpigmented lesions with histological evidence one must institute endometriosic therapy which will promote integral management of the problem: from the reproductive symptomatic aspects.