One hundred seventy-three patients were treated 256 times with chemotherapy supported by autologous bone marrow transplantation during the past 9 years. The two most commonly used protocols were (cyclophosphamide 1,600-2,400 mg/m2 + adriamycin 80 mg/m2 + ACNU 3 mg/kg) and (cyclophosphamide 1,600-2,400 mg/m2 + adriamycin 100 mg/m2 + CDDP 100-150 mg/m2). Among 115 patients in the therapeutic setting in which two courses were usually given, 75 were evaluable and the overall response rate was 42.7% with 12.0% CR rate. Breast and pediatric groups responded well; the response rate in breast cancer was 67.9% with 21.4% CR rate. Two patients with breast cancer who had multiple distant metastases and 2 pediatric patients are now alive with NED after 5 years of the treatment and seem to have been cured. The results in adjuvant settings have also been quite promising, e.g., 79.4% 5-year survival probability among breast patients mainly in stage III. Although drops of blood cell counts to the nadirs (WBC counts: less than 100-300) could not be prevented, the periods of myelosuppression appeared to have been effectively shortened so that the patients could be safely managed with intensified general supportive measures. Platelet counts are usually less affected, but the recovery is slower than for WBC counts. There were 13 patients who died within 10 weeks of the initiation of the treatment. Two of them succumbed to sepsis, and progressive disease was the cause of death in 8 patients whose terminal phases were undoubtedly affected by some infectious problems. We have shown that there are inverse relationships between infused numbers of CFU-GM and marrow recovery judged by the duration of neutropenia and the time required for neutrophils to recover over 500. Our recent laboratory experiments testing CFU-E, BFU-E and CFU-Mk in addition to MNC counts and CFU-GM showed that vulnerabilities of marrow progenitors seem to differ from cell lineage to cell lineage. This must therefore be taken into careful consideration in pursuing marrow transplantation.