The complete remission (CR) rate in children with acute lymphoblastic leukemia (ALL) who received vincristine (VCR) plus prednisone (PRED) alone for induction is > 90%, and has not improved with the use of more intensive regimens. In adults with ALL, using the same regimen, a CR rate of only 50% is frequently quoted, and is apparently based mainly on unpublished data on only 13 patients from an early Acute Leukemia Group B protocol. We reviewed the case records of 43 adults with previously untreated ALL seen between July I , 1966 and December 3 I , 1978 who received VCR + PRED alone for induction. A CR rate of 66% was achieved and compares to an overall figure of 61% from 162 patients collected from the literature. The CR rate was age dependent with 21/29 (76%) < 50 years of age achieving a CR compared to 4/19 (29%) who were 2 50 years of age (P < 0.02). The median duration of CR was 8.3 months. For those who achieved a CR, the median survival was 19 months compared to five months for those who either failed to achieve a CR or who achieved only a partial remission (P = 0.004). All patients who achieved a CR received maintenance therapy, and approximately one-half also received CNS prophylaxis with intrathecal methotrexate. The incidence of isolated CNS relapse was 1 1 % in those who received CNS prophylaxis compared to 20% in those who did not.From these data and a review of the literature, we conclude that approximately twothirds of adults with ALL will achieve a CR with the use of VCR + PRED alone. The median duration of CR, however, is < one ycar and the median survival is approximately two years. Whether the use of more intensive induction, consolidation, and maintenance regimens will improve these results remains to be established.