Two female patients, 42 and 30 years old, respectively, died of acute nonlymphocytic leukemia 43 and 38 months, respectively, after a subsequent treatment: chemotherapy for one and irradiation and chemotherapy for the other, following excision of a malignant glioma. At the time of death, both seemed to be in complete remission of their brain tumor. Both had been treated with procarbazine and nitrosoureas. The latter were responsible for severe myelosuppressive episodes and seem to have played an essential role in the induction of the leukemia. In one case, a myelodysplasia was observed before the onset of the AL and the diagnosis of refractory anemia with excess of blasts seemed warranted. Secondary acute leukemias are rare in the evolution of malignant gliomas and the usefulness of subsequent radiochemotherapy cannot be questioned at the present time. The risks involved in this therapy are minor when compared to the short-term fatal prognosis of this type of tumor.