Objective: To study the clinicopathological characters of malignant ovarian tumors during pregnancy. The rationale for appropriate management was discussed. Methods: Twenty-one cases of malignant ovarian tumors complicating pregnancy treated between 1985 and 2002 were reviewed retrospectively. In reference with the reports from the current literatures, the rationale of the treatment for the best outcome of both mother and child was discussed. Results:In the patients reviewed, 9 were found with malignant germ cell tumors of the ovary, 6 with low malignant potential tumors, 4 with invasive epithelial tumors, and 2 with sex cord-stromal tumors. Sixteen (76. 2%) of the patients diagnosed in stage Ⅰ, and all had achieved complete response to the treatment. Three of the four patients in advanced stage died, of which two were invasive epithelial cancers and one stage Ⅳendodermal sinus tumor. All patients had surgery, and fourteen of them got conservative surgery. All sixteen patients accepted for chemotherapy took adjuvant chemotherapies after abortions or deliveries. Fourteen healthy live births were recorded in this group and there were no documented birth defects, but one died of respiratory distress syndrome. Conclusion: The managements of malignant ovarian cancers during pregnancy differed in different histological types. In ovarian borderline tumors and malignant germ cell tumors including stage Ⅰ,Ⅱ, and Ⅲ, surgery can be conservative. For advanced epithelial cancers, aggressive surgery should be instituted. Chemotherapy could be considered for the malignant germ cell tumor during the second and third trimester. Ovarian borderline tumors should not take chemotherapy. Epithelial cancer should be given combination platinum-based chemotherapy. Hysterectomy during pregnancy is rarely indicated unless it contributes significantly to tumor debulking, and pregnancy often could be allowed to continue until near-term. Objective: To study the clinicopathological characters of malignant ovarian tumors during pregnancy. The rationale for appropriate management was discussed. Methods: Twenty-one cases of malignant ovarian tumors complicating pregnancy treated between 1985 and 2002 were reviewed retrospectively. current literatures, the rationale of the treatment for the best outcome of both mother and child was discussed. Results: In the patients reviewed, 9 were found with malignant germ cell tumors of the ovary, 6 with low malignant potential tumors, 4 with invasive epithelial tumors, and 2 with sex cord-stromal tumors. Sixteen (76.2%) of the patients diagnosed in stage I, and all had achieved complete response to the treatment. Three of the four patients in advanced stage died, of which two were All patients had surgery, and fourteen of them got conservative surgery. All sixteen patients acce pted for chemotherapy took adjuvant chemotherapies after abortions or deliveries. Fourteen healthy live births were recorded in this group and there were no documented birth defects, but one died of respiratory distress syndrome. Conclusion: The managements of malignant ovarian cancers during pregnancy differed in different histological types. In ovarian borderline tumors and malignant germ cell tumors including stage I, II, and III, surgery can be conservative. For advanced epithelial cancers, aggressive surgery should be instituted. Chemotherapy could be considered for the malignant germ cell tumor during the second and Third trimester. Ovarian borderline tumors should not take chemotherapy. Hysterectomy during pregnancy is rarely indicated unless it contributes significantly to tumor debulking, and pregnancy often could be allowed to continue until near-term.