Objective To study the incidence of malignant change, diagnosis and management of mature cystic teratomas in postmenopausal women.Methods Twenty cases of mature cystic teratoma in postmenopausal women admitted to our hospital between January 1977 and January 1997 was retrospectively reviewed and evaluated.Results The number of postmenopausal patients with mature cystic teratoma (20) accounted for 7.6% of the total number of patients with benign ovarian teratomas (263). There were 3 cases of malignant change, which were squamous carcinoma, carcinosarcoma, and digestive gland epithelial carcinoma. The incidence of malignant change was 15%.Conclusion In postmenopausal women, mature ovarian cystic teratoma should be treated as lowly malignant and should be paid much attention.