Two cases of complete remission plus one almost complete and another partial response of undifferentiated, invasive epithelial malignant thymoma using the combination of cisplatin, vinblastine, and bleomycin (PVB), are reported in four patients treated with this combination. Radiotherapy was instituted after completing the fourth course of chemotherapy in three patients. One patient died from intercurrent infection after the fourth cycle of combination chemotherapy. Three patients remain free of disease at the end of the treatment program. PVB appears to be highly active in this disease and deserves more extensive evaluation in multicenter clinical trials.