One hundred and twenty adult patients with acute lymphoblastic leukaemia were treated over a 10 year period with an intensive treatment protocol including induction with vincristine, prednisolone, adriamycin and L asparaginase, early intensification with 4 cycles of cytosine arabinoside plus VP 16 followed by BCNU and cyclical maintenance therapy consisting of sequential administration of 4 chemotherapy combinations, together with prophylactic in-trathecal methotrexate. 108/120 (90%) achieved initial complete remission (CR). Factors which predicted for CR were absence of bleeding at initial presentation and LDH < 300 Iu. The overall median duration of remission was 12 months with 19% of patients in continuous complete remission for 5 years or more. Among the poor prognostic factors for continuous complete remission were race (black patients) WCC > 30 × 109/1, bleeding at presentation, splenomegaly at presentation, phenotype other than T and age > 35 years. The effect of adverse prognostic features was cumulative but race was the most significant factor overall with no black patients surviving for more than 24 months. There was a significantly higher rate of decreased compliance with maintenance therapy among black patients, which may have been responsible for the adverse influence of race. These results suggest that the role of maintenance chemotherapy is significant in maintaining prolonged complete remission in adult acute lymphoblastic leukaemia. © 1991 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.