The efficacy and toxicity of high-dose chemotherapy with autologous bone marrow transplantation (ABMT) was studied in 32 patients with untreated limited small-cell bronchogenic carcinoma (SCBC). Ten patients received three courses of induction therapy consisting of vincristine (VCR) (1.5 mg X 2), ifosfamide (5 g/m2), and Adriamycin (Ad; Adria Laboratories, Columbus, Ohio) (60 mg/m2). Patients then received two courses of intensification therapy with cyclophosphamide (CYT) (4.5 g/m2), 4' demethyl-epipodophyllotoxin-d-D-ethylidene glucoside (VP-16-213) (600 mg/m2) and VCR (2 mg) with ABMT. Another 22 patients received induction therapy with VCR, CYT (600 mg/m2), Ad (50 mg/m2), and VP-16-213 (180 mg/m2). All 22 patients also received intensification therapy of the same dose of CYT (4.5 g/m2) and VP-16-213 (600 mg/m2). Nine patients also received high-dose methotrexate (MTX), four patients received Ad (40 to 60 mg/m2), and two patients received both Ad and MTX. After intensification, patients received elective prophylactic brain irradiation (3,000 rad) and chest irradiation (5,000 rad). After induction therapy, there were 13 (41%) complete remissions (CR) and 17 (53%) partial remissions (PR). After intensification therapy, there were 22 CRs (69%) and 10 PRs (31%). Median survival for all patients was 14 months (range, 5 to 59+). Of the 13 patients who received intensification therapy in CR, five remain disease free (DF), four for 4 years or longer. Of the nine patients to achieve CR with intensification, only one is DF. No patient died during intensification. In conclusion, intensification with high-dose chemotherapy can increase the CR rate, and this approach is most likely to show long-term benefits in patients with minimal disease (CR) at the beginning of intensification therapy.