The clinical courses of 82 women with gestational trophoblastic tumors were evaluated in accordance with International Federation of Gynecologists and Obstetricians staging, traditional criteria and the modified World Health Organization prognostic scoring system. The overall remission rate was 79.3% (65/82), and the mortality rate was 20.7% (17/82). All the patients with nonmetastatic stage I disease and all with prognostic scores less than or equal to 4 attained remission, whereas patients at high risk and with stage IV disease had the lowest remission and survival rates. The results support the validity of each system. However, the World Health Organization scoring system, a combination of traditional criteria and International Federation of Gynecologists and Obstetricians staging seemed to be the most reliable for predicting treatment failures.