We report a 73 years old woman presenting with a right ovarian tumor. Preoperative carcinoembryonic antigen and CA-125 levels were above normal levels. The patient was operated, performing a bilateral oopho-rectomy an appendectomy. The pathological study of the surgical piece reported a mucinous ovarian cystic adenocarcinoma that infiltrated the wall but did not reach the capsule. A mucinous cystadenoma was found in the contralateral ovary. A mucinous adenocarcinoma was detected in the appendix, involving the wall but sparing the serosa. The patient was subjected to chemotherapy and six months after the first operation a tumor relapse was detected. A new excision was carried out and the patient continues with adjuvant chemotherapy. The ovarian an appendiceal tumors could be synchronic or a primary and secondary localization.