The purpose of this study was to evaluate the effectiveness of unpurged autologous stem cell transplantation (ASCT) for chronic myelogenous leukemia (CML) and its impact on the survival of patients in first and late chronic phase (CML-CP) including those resistant to or unable to tolerate interferon alfa (IFN-alpha) therapy. Between 1982 and 1993, 73 patients with CML who underwent ASCT were evaluated. Twenty-eight patients had signs of transformation, 20 were in second or subsequent CP, 22 had CML-CP and had shown resistance to or were unable to tolerate IFN-alpha therapy, and there had Philadelphia (Ph) chromosome-negative CML. Survival of patients in CML-CP who underwent ASCT was compared to controls who were in first CP receiving INF-a therapy. Patients and controls were matched for age, decade of therapy, response to IFN-alpha therapy (resistance vs toxicity) and the time to ASCT (study group) vs time to resistance (control group). Nine 12% patients failed to achieve hematologic recovery, and five (7%) had early death secondary to toxicity. Twenty-seven (58%) patients who received transplants in advanced-stage CML and 18 (82%) transplanted in CML-CP achieved complete hematologic remission (CHR). The incidence of complete cytogenetic response was 10 and 14%, respectively. The median survival of these two groups of patients was 5 and 34 months, respectively (P < 0.001). However, the survival of patients in CML-CP was not significantly different from controls (34 vs 49 months; P = 0.17). We conclude that unpurged ASCT does not prolong the survival of patients in CML-CP who are resistant to IFN-alpha therapy. Progress in autotransplantation in CML might require innovative approaches to eradicate the leukemic cells from the autologous stem cells prior to transplants.