We report a 54-year-old woman with ovarian strumal carcinoid in association with dermoid cyst and mucinous cystadenoma in the same ovary and who had markedly high serum levels of CEA (202 ng/ml), CA125 (710 U/ml), and CA19-9 (11,500 U/ml). These tumor markers were not found in the thyroid tissue or carcinoid by immunohistochemical methods, but their serum levels decreased to below the cutoff levels after surgery. In our case, the change of serum levels of these tumor markers may be useful for the follow-up after surgery.