Allogeneic stem cell transplantation (SCT) plays a central role in chronic myeloid leukemia (CML) because it remains the only treatment with proven curative potential. For this reason, SCT has been more frequently performed in CML than in any other disease. The susceptibility of CML to the graft-versus-leukemia (GVL) effect and our ability to monitor minimal residual disease are particular features that place this disease at the forefront of GVL research. This review describes the mechanism of cure of CML by SCT, current results of transplantation, factors determining outcome, management of relapsed or persistent disease, and recent treatment advances.