Abstract: The efficacy of high dose carboplatin therapy with auotologous bone marrow transplantation(ABMT)was studied in five patients with extensive small cell lung cance (SCLC). Among of them, 4 males and 1 female, the average.age was 40. 6 years (range, 19 to 55 years), the median durationfrom dignosis to ABMT was approximately 8. 6 months (range, 3 to 14 months). Four patients hadreceived prior induction chemotherapy and one patient received the surgical therapy. At the begin-ing of high dose therapy, 3 patients had achived partial remission (PR) and other patients had notresponded to routine chemotherapy. The dose of carboplatin ranged from 560 to 1375 mg/mZ. Atthe end of high dose carboplatin therapy with ABMT, there were 4 complete remission (CR) andone case was not changed. The duration of CR ranged from 1. 5 to 18 months