Abstract: Objective To investigate the role of P73α in relation to cellular chemosensitivity in cultured human bone marrow mesenchymal stem cells. Methods To construct the retrovirus vector expressing P73α and transfect human bone marrow mesenchymal stem cells.Chemosensitivity and apoptosis were examined in the exogenous over-expressed cells. Results Our results showed that retrovirus can successfully induce human P73α expression in bone marrow mesenchymal stem cells, over-expression of ectopic P73α resulted in a significant increase of cellular sensitivity to cisplatin. Enhanced chemosentivity in P73α transfected cells was attributed by the increase of cellular apoptosis. Moreover, co-activation of pro-apoptotic factors Bax and P21 was observed in the transfected cells after cisplatin treatment. Conclusion Our findings suggested that P73α is an important determinant of cellular chemosensitivity to cisplatin in the human bone marrow mesenchymal stem cells.