There are a few case reports describing conversion to normal sinus rhythm after a propofol injection in tachyarrhythmic patients. We managed two cases of 52 year old males complaining of chest pain and dyspnea. We diagnosed them with atrial flutter and idiopathic ventricular tachycardia respectively. Initially they were treated with antiarrhythmic drugs but conversion to normal sinus rhythm was not achieved. Therefore, we decided to use electrical cardioversion. For sedation during electrical cardioversion, we injected propofol 2 mg/kg and 2% lidocaine 1 mg/kg. A few seconds later, conversion to normal sinus rhythm was achieved without electrical cardioversion in both cases. Thereafter normal sinus rhythm continued on the ECG and they were discharged.