Abstract Four patients with limited disease small cell carcinoma of the lung were treated with high-dose cyclophosphamide (120 mg/kg over days 1 and 2), BCNU (400 mg/m 2 over days 1 and 2) and VP-16 (200 mg days 1–5) used as intensification treatment after conventional chemotherapy. To ameliorate hematopoietic toxicity, autologous bone marrow cells collected and cryopreserved prior to treatment were reinfused on day 8. In three patients clinical response was evaluable. Two achieved a complete remission: one died without evidence of tumor after 3 months; the other had a regional relapse after 6 months. One patient who had progression of disease on conventional chemotherapy was refractory to high-dose treatment. Three patients developed diffuse interstitial pneumonitis 3 weeks after treatment and two died of respiratory failure. High-dose intensification chemotherapy with autologous marrow reinfusion may complement the effects of standard combination chemotherapy in small cell carcinoma of the lung. The current status of this approach is reviewed.