Endometriosis is a benign disease defined as the extra-uterine implantation and proliferation of tissue similar to endometrium (glands and stroma), causing a chronic inflammatory response and adhesions that distort anatomy. The extra-gonadal involvement is rare, but reports of intestinal endometriosis have increased substantially, mainly affecting the sigmoid colon and rectum; isolated involvement of the cecum is rare, even more so in a postmenopausal woman without use of hormone replacement therapy. We report the case of a postmenopausal woman with intestinal obstruction surgically suggestive of malignancy; however, pathological examination revealed endometriosis.