A 32-year-old female patient who had Philadelphia chromosome-positive acute lymphoblastic leukemia underwent cord blood transplantation while in her second remission. However, she had a hematological and central nervous system relapse 3 months later. After reinduction with imatinib mesylate, unmanipulated peripheral blood stem cell transplantation was performed from the patient's haploidentical mother with a reduced-intensity conditioning regimen. Rabbit antithymocyte globulin, tacrolimus, and methylprednisolone were used for prophylaxis of graft-versus-host disease. Engraftment of neutrophils was observed on day 12, and complete donor chimerism was obtained by day 24. The posttransplantation course was uneventful. Although the patient had a relapse 10 months later, this case demonstrated that transplantation from a haploidentical donor is clearly a feasible alternative for patients who desperately need rescue transplantation.