The cardiovascular disease and sudden death due to the occlusion of coronary artery increases in women after menopause. In this study, it was aimed to research the effect of genistein that has been used to decrease the symptom of menopause in women, on the ischemia reperfusion induced arrhythmias. 64 Female and 12 male, 6-7months old Sprague Dowley rats were used in this study. Genistein was applied daily for four weeks in 100ug/kg dose intraperitoneally in one group and acutely in other group, before reperfusion in 1mg/kg dose intravenously. Six minutes myocardial ischemia were produced by the ligation of ramus interventricularis branch of left coronary artery (LAD) and six minutes of reperfusion by releasing of this artery. The type and duration of arrhythmias and the blood pressure recorded in every group during ischemia and reperfusion were analyzed and compared by using one-way ANOVA test and the incidence of arrhythmia and the survival rate by Ki square test. Genistein had no effect on the ischemia and reperfusion induced arrhythmias in male and ovariectomized female rats.