Aim To study the effect of rat transient myocardial ischemia/reperfusion and the oxidative stress of C₂C₁₂ cells on the expression of Krüppel-like factor 4(KLF 4) gene.Methods Rat model of transient myocardial ischemia/reperfusion was established by occluding and relaxing of left coronary artery.C₂C₁₂ cells were treated with H₂O₂(1 mmol/L) to build the oxidative stress model.RT-PCR and Western blotting were performed to determine the changes of KLF 4 expression.Results Transient myocardial ischemia/reperfusion induced obvious accumulation of KLF 4 mRNA in rat.Oxidative stress distinctly raised the KLF 4 mRNA and protein levels in C₂C₁₂ cells.Conclusion High expression of KLF 4 gene was induced by rat transient myocardial ischemia/reperfusion and the oxidative stress of C₂C₁₂ cells.