For patients with ALL we must be able to identify clearly both standard and high-risk patients. For standard-risk patients in whom life expectancy is long, therapy regimens must be designed to provide optimal control with minimal short- and long-term toxicity. For patients with high-risk ALL, methods must be found to circumvent the problem of early acquisition of drug resistance by the leukemic lymphoblasts. For patients with AML, more work must be done to improve the results of remission induction. But the major problem for these patients is the maintenance of a remission once it is obtained. Perhaps one of the critical factors in AML is the interrelationship of normal and leukemic marrow elements in therapy response. Disease-free survival time must be improved before considerations of CNS prophylaxis and cessation of therapy can be approached.