Abstract: Ovarian cancers are the most common gynecological neoplasms，which has the highest mortality rate of cancers of the reproductive organs，because of lack of effective early diagnostic tool. DNA methylation is the first epigenetic changes discovered by human. Methlation of RASSF1A、BRCA1 and hMLH1 genes play an important role in the development of ovarian cancers. Detection of these genes could help early cancer diagnosis. However, some DNA methylation, like hMLH1, decline the sensitivity of chemotherapy drugs to tumor cells. Demethylation drugs which can reexpress those genes may improve the effect of chemotherapy and prognosis. In this review，we have summarized the newest researchs of DNA methylation changes in ovarian cancer.

Key words: DNA methylation, Ovarian neoplasms, Carcinoma, Diagnosis, Therapy