SummaryThe drug of choice to be used in the treatment of chronic myeloid leukaemia is Myleran. Total clinical and haematologic remissions are generally, obtained.Other antimitotic agents are efficient, especially in Myleran resistant cases. Radioactive isotopes, such as P32 and A1*" can also be used.Due to more protean aspect of the disease, the treatment of lymphoid leukemia is more difficult. The best drug in such a case is chlorambucil, which can be associated with Röntgen therapy in cases with large lymphadenopathies, or with corticoid hormones in cases with anaemia.Other chemotherapeutic agents have been tested, such as Fe3', Dopan, Sarcolysine, Degranol and Endoxan, but none of them seem better than Myleran and Leukeran.