We report the data obtained from the European Bone Marrow Transplant Registry for patients with CML who received autologous transplantation (AT) in chronic phase (CP) because alpha-IFN was ineffective. Forty-one CML patients (median age: 40.5 years; median Sokal index: 0.78) were included in this study. Bone marrow (16 cases) or blood (25 cases) progenitor cells were collected at diagnosis in 19 patients, during stable chronic phase or while the patient had cytogenetic (Cy) or complete hematologic response (CHR) in the other 22, and were manipulated ex vivo in 10 cases. The conditioning regimen consisted of busulfan associated with other chemotherapeutic regimens in 36 cases. Two patients died from interstitial pneumonitis (one case) and hemorrhage (one case). From the date of AT, the estimated probability of survival for the 41 patients was 84 +/- 13% and 51 +/- 29% at 2 and 4 years, respectively. Considering the 39 evaluable patients, the actuarial probability of achieving CHR, major and complete CyR 2 years after AT was 92 +/- 9%, 46 +/- 17%, and 30 +/- 15%, respectively. The Sokal score at diagnosis and the achievement of hematologic response after transplant were of prognostic importance. We suggest that a significant proportion of CML patients not responding to alpha-IFN may benefit from AT.