Acute lymphoblastic leukaemias which are, at the present time, curable are those which go 01.cfhçinto remission following treatment with the combination prednisone-vincristine, in which lymphoblastic meningitis does not occur after preventive treatment of the central nervous system and which show no recurrence during maintenance chemotherapy. In order that the largest possible number of these potentially curable patients may be transformed into truly cured cases, we propose here a simple outline of treatment: induction of remission by one month of treatment with prednisone 40 mg/m2/day and vincristine 1.5 mg/m2/week, immediately followed by treatment of the central nervous system: 2 400 rads to the brain down to C2 in two weeks and an half and 6 injection (2 per week) of intrathecal methotrexate 5 mg/m2/injection and maintenance chemotherapy for two years with 6 MP, 25 to 50 mg/m2/day and parenteral methotrexate, 10 to 15 mg/m2/week, then immunotherapy with BCG, for a minimum of three years and a maximum of five.