Intermittent or transient left branch blook is a transient intraventricular conduction defect which was reported by many authors. Although variable etiologic and predisposing causes were considered, myocardial ischemia and hypertension were most important pathogenic factors of intermittent left bundle branch block. We had experienced one case of intermittent LBBB with hypertension and unstable angina and it was evoked by tachycardia, so we reported this case of 50-year old man with brief review of literatrue.