Non-gestational choriocarcinoma (NGCO) is a rare primary ovarian cancer with poor prognosis. It is important to distinguish it from gestational ovarian choriocarcinoma (GCO), because there are different treatment options. However, it is difficult to distinguish the two types by routine histologic, ultrastructural, or immunohistochemical examination. The authors present NGCO in a 41-yearold woman, which was confirmed by DNA polymorphism analysis. All tested microsatellite markers had identical DNA profiles with the same allelic sizes between tumor and normal myometrium of the patient, indicating that both tissues originated from the same person. The results confirmed that the tumor was non-gestational in origin. Although the tumor was large, the authors performed handassisted laparoscopic surgical (HALS) staging. After three cycles of combination chemotherapy and surgery, the patient has not had any evidence of disease 48 months after treatment. This case demonstrates the usefulness of HALS staging and DNA polymorphism analysis in NGCO.