In cases of gestational choriocarcinoma, the period from antecedent pregnancy to the onset of the disease (latent period) is watched as a risk factor. When this period was calculated in about 106 cases collected, a period of more than 2 years was found in 8 cases. Therefore, concerning these 8 cases, investigation was made into the chief complaint, the kind of antecedent pregnancy, clinical stage classification, hCG value on diagnosis, histological classification and prognosis. As to the kind of antecedent pregnancy, 7 cases out of 8 were hydatidiform moles (87.5%). However, in 98 cases with a latent period within 2 years, the number of cases of mole antecedent was 54 (55.1%). With the lengthening of the latent period the incidence of antecedent hydatidiform mole tended to increase. Moreover, in the histological classification, particularly in our CPV classification, 7 cases were seen to be P type or V type. In the long-term cases over 2 years a high degree of histological malignancy was observed compared with those of latent periods of less than 2 years.