Over a 3 year period (1989-1991), 49 patients who underwent autologous stem cell transplantation (ASCT) for chronic myelogenous leukemia (CML) in chronic phase were reported to the European Bone Marrow Transplant Registry. Most patients had bad prognostic factors. The results were analyzed by 1 September 1993. Hematological recovery was observed in 45 cases and was significantly quicker after blood stem cell transplantation (n = 30) than after BMT (n = 19). Five patients died early and five other patients did not achieve a complete hematological response (CHR) following ASCT. Of the 39 patients who achieved CHR, 34 are still alive 17 to 52 months after ABSCT. Fifteen of the 34 patients who had cytogenetic evaluation exhibited a major response (> or = 65%, Ph-negative metaphases). The actuarial risk of transformation for the 44 evaluable patients was 28.1 +/- 15% (95% CI) and the actuarial survival at three years was 81.5 +/- 15% (95% CI). No factors were found to significantly influence the response rate or the patients' survival. These encouraging results suggest that ASCT by itself could play a role in prolonging survival in CML patients.