Colo-rectal endometriosis represents a rare pathological event. Exceptionally, a malignant colo-rectal endometrioid carcinoma arising from endometriosis has been reported. In the present case, we describe a 32 year-old woman with clinical and radiological signs of large bowel sub-occlusive syndrome. Histologically, a sigmoid endometrioid adenocarcinoma associated with submucosal foci of eutopic endometrium was observed. Moreover, endometriotic tissue was observed at the level of the colonic left flexura and appendix. Colo-rectal endometriosis must be considered among risk factors for the development of large bowel adenocarcinoma in young female patients.