Placental site trophoblastic tumor is a rare disease. Most benign cases of this disease show a few mitotic figures of the tumor while recurrent cases usually have more than 5 mitoses per 10 high-power fields. The present case was primarily treated by hysterectomy and chemotherapy and had 2 mitoses in 10 high-power fields. After 1 years and 4 months of therapy the patients was diagnosed as ovarian metastasis because of gradually increasing serum beta-human chorionic gonadotropin (hCG) level and abnormally high fluid levels of beta-hCG and human placental lactogen (hPL) punctured from her cystic ovarian tumor. This recurrent case was further treated with another regimen of chemotherapy for 7 courses, and the serum beta-hCG level had decreased at present. This report describes the recurrent case and discusses the histology of a few mitotic figures, electron microscopic findings, and results of the DNA fingerprint analysis of the primary tumor.