Forty-five patients were treated for chronic granulocytic leukemia (CGL) in transformation by intensive chemotherapy (23 patients) or radiochemotherapy (22 patients) followed by autologous transplantation of bone marrow (17 patients) or blood-derived hematopoietic stem cells (28 patients). Hematopoiesis was reestablished in most evaluable patients and was significantly more rapid in previously splenectomized patients or in those receiving more than 10 X 10(8) nucleated cells/kg. However, partial or complete failure of engraftment was observed in 11 patients, in most cases after autografting with marrow cells. The median survival of all patients was 4.5 months. The major cause of death was the rapid recurrence of the blast cells not eradicated by the conditioning regimen. However, 4 of the 11 patients treated during the accelerated phase are still alive in the chronic phase, 17, 23, 35, and 54 months after autografting. These results and the restoration of hematopoiesis without the Philadelphia chromosome in 5 patients suggest that autografting could be used in CGL before the onset of the blast crisis.