Primary tumors of the appendix are rare and most of them are unrecognized preoperatively, presenting as appendicits, pelvic masses or with no typical abdominal pain. Two cases of mucinous tumors of the appendix presenting as primary ovarian tumors are described. It is important for the gynecologist-oncologist to include mucinous tumors of the appendix into the differential diagnosis of any case of mucinous ovarian tumor and peritoneal pseudomyxoma, especially when these tumors are associated with extraovarian disease.