Sequential chemotherapy with vincristine, daunorubicin, cyclophosphamide, and prednisone doses was administered to 57 adult patients with acute lymphoblastic leukemia (ALL). Complete remission (CR) was achieved in 51 (89%, 95% confidence intervals, [CI] 78-96%). Among patients achieving CR, 62% were in CR after one sequence of chemotherapy, 23% after two sequences, and 5% after three sequences. Six patients (11%) had resistant disease. All patients experienced profound myelosuppression. Median time to recovery of neutrophils > 0.5 x 10(9)/1 was 22 days (range: 5-89 days), and of platelets > 100 x 10(9)/1 21 days (range: 0-45 days). Nonhematologic WHO grade 3 or more side effects consisted predominantly of hyperbilirubinemia (7%), mucositis (5%), nausea and vomiting (2%), and cutaneous toxicity (1%). Severe infectious complications occurred in only 14% of cases. One patient (2%, 95% CI 0-9%) died of therapy-related toxicity while in early CR. We concluded that sequential use of prednisone seemed at least as effective as continuous administration at the expense of a few adverse side effects.