Early intensive therapy might be critical in improving failure-free survival for children with acute lymphoblastic leukemia. Between 1973 and 1977, 107 children received vincristine and prednisone (VP) induction and 30 received the same two agents plus an anthracycline (VPA). Ninety-nine of the VP-treated group and all 30 of the VPA-treated patients achieved complete remission. At a median observation time of 10 years, 59 of 137 children remain in continuous complete remission. Failure-free survival was 37% for the VP group and 63% for the VPA group (p = 0.02). Failure-free survival for boys who received VP was 28%, compared with 68% for boys who received VPA (p = 0.007). All 11 extramedullary relapses and all seven relapses occurring beyond 3.8 years from diagnosis (three testicular and four bone marrow) were observed among the VP group. We conclude that use of an anthracycline during remission induction therapy influenced failure-free survival and that early results of successful antileukemic therapy in children must be confirmed by follow-up progress reports.