objective To evaluate effect of postconditioning with electrical stimulation of vagus never on myocardial ischemia reperfusion injury in rats. Methods Forty male Sprague-Dawley rats aged 8 weeks and weighing 250-350g were randomly allocated into four groups (n=10 in each group): sham group (S group); ischemia reperfusion group (IR group); ischemia preconditioning group (IPC group) and postconditioning with electrical stimulation of vagus never group (POES group). The myocardial ischemia reperfusion model was preparated by ligation of left anterior descending coronary artery (LAD) for 30 min followed by 120 min reperfusion. During process of ischemia and reperfusion, HR and MAP were recorded and the rate pressure product (RPP) at every measuring point was calculated as the index of myocardial oxygen consumption. Arrhythmia was recorded during ischemia and initial period of reperfusion. At the end of reperfusion, blood samples were collected to assay serum concentrations of CK-MB, and cTnI. At the end of experiment, the infarct sizes was assessed from excised hearts by Evans blue and triphenyltetrazolium chloride (TTC) staining. Results The infarct size (IS%) was 71.6±8.7% in IR group, 36.0±12.5% in IPC group and 46.5±11.9% in POES group, respectively, and serum concentration of cTnI was 0.99±0.14ng/ml in IR group, 0.37±0.08ng/ml in IPC group and 0.40±0.08 ng/ml in POES group. Compared to the IR group, the IS% and serum concentrations of cTnI and CK-MB in IPC and POES groups were significantly reduced, rate of ventricular arrhythmia during initial period of reperfusion in the IPC and POES groups were also significantly reduced. Compared to IPC group, the IS% was significantly increased in the POES group. Conclusions Postconditioning with electrical stimulation of vagus never can attenuate myocardial ischemia reperfusion injury in rats. However, cardioprotection provided by postconditioning with electrical stimulation of vagus never is weaker than that by ischemia preconditioning.