The results of treatment of 84 acute leukaemia patients during a 15-year period are reported. Sixty-three of the patients suffered from acute myeloid leukaemia, 14 had blastic crisis of chronic leukaemia and 7 had acute myelomonocytic leukaemia. Administration of prednisolone + purinethol, prednisolone + vincristine, and prednisolone + vincristine + purinethol combinations resulted in partial remission. The best results were achieved with the combination ARA-C + thioguanine + prednisolone, which produced complete remission in 2 out of 8 cases. One patient was refractory to this treatment.