Abstract: Objective To explore the effects of different approaches of stem cell therapy in patients with leukemia on haptoglobin (Hp). Methods Four patients treated by mesenchymal stem cells (MSC) with hematopoietic stem cells cotransplantation (HSCT), and two patients treated by hematopoietic stem cell transplantation (HSCT) were as objects of the study. Haptoglobin in the plasma, collected from different therapeutic stages, of six patients was separated by two-dimensional gel electrophoresis (2-DE), followed by the identification with MALDI-TOF/TOF mass spectrometry. Results The abundance of haptoglobin alpha and beta chains with different modification decreased along with an increasing therapeutic time window. This tendency was more significant in HSCT group. Conclusion The haptoglobin may be a potential biomarker for monitoring prognosis in patients with leukemia treated by stem cell transplantation.