We report a female patient with relapsed Philadelphia chromosome-positive acute lymphoblastic leukemia remaining in long-term second remission after high-dose radiochemotherapy followed by autologous stem cell rescue with bone marrow showing evidence of residual disease. The Philadelphia chromosome and a positive signal for the BCR/ABL p185 translocation by the polymerase chain reaction were detected in the harvested marrow. After mafosfamide-purged marrow failed to engraft, her unpurged 'back-up' bone marrow was also infused. Control marrow examinations after recovery were repeatedly positive for the BCR/ABL translocation on PCR analysis turning negative 30 months after high-dose therapy. She remains in unsustained complete clinical remission for 48+ months showing no evidence of leukemia by cytological and cytogenetic analyses.