A malignant strumal carcinoid with widespread metastases resembling a well-differentiated thyroid follicular carcinoma is described. Strumal carcinoid is a rare ovarian tumor which usually behaves in a benign manner. Only one malignant case has been reported in the literature and in that case the carcinoid element metastasized. The clinical, histological, and immunohistochemical findings of the current case together with the relationship between strumal carcinoids and struma ovarii are discussed.