Aim To investigate the effect of Krüppel-like factor 4(KLF4)overexpression on doxorubicin-induced apoptosis of rat myocardiocytes H9C2.Methods Trypan blue staining and cytometry were applied to detect apoptosis;Western blotting was applied to determine expressions of KLF4 and apoptosis-related gene poly ADP-ribose polymerase(PARP).Results Trypan blue staining and cytometry results showed that doxorubicin could induce apoptosis of H9C2,and the apoptosis rate in KLF4-overexpression group was much higher than that of vector control group,which was 87.90%.Western blotting results showed that doxorubicin treatment could promote KLF4 expression in H9C2 cells,and the expression of PARP fragment was also up-regulated dramatically in KLF4-overexpression group.Conclusion KLF4 could promote doxorubicin-induced apoptosis of H9C2 cells,which potential mechanism may be involved with PARP.