Forty-two of sixty-seven patients (62.7%) treated for high-risk metastatic trophoblastic disease achieved and maintained complete remissions. The survival rate was significantly improved in those patients with scores lower than 8 according to a modification of the World Health Organization (WHO) prognostic scoring system. A low score was associated with a higher probability of response to single-agent therapy, although the difference was not statistically significant. The score, however, was significantly associated with response to multiagent chemotherapy with methotrexate, actinomycin D, and cyclophosphamide (P = 0.0004). Therefore, future trials of new combinations of chemotherapy in high-risk patients should be stratified according to the patients' prognostic scores.