Ovarian cancer often presents at an advanced stage, but tends to be an intra-peritoneal disease that respects peritoneal planes. Thus, colo-rectal perforation of the tumor is an extremely rare presentation. The surgical treatment of malignant colo-ovarian fistula should include complete cyto-reduction at the same time as the treatment of the fistula. However, prognosis remains poor, because of the advanced stage of neoplasia. We report the case of a patient with an ovarian malignant tumor perforating into the recto-sigmoid colon. CT scan was the cornerstone of the radiological diagnosis. We managed to perform a complete cyto-reduction, including an en-bloc resection of the uterus, the mass, adnexa and recto-sigmoid with removal of the associated pelvic abscess.