AIM The aim was to evaluate the antiarrhythmic effects provided by carvedilol, and compared with propranolol in several arrhythmia animal models. METHODS Experiments were performed in 5 arrhythmic animal models, inhalation of chloroform to induce ventricular fibrillation (VF) in mice, ouabain induced or aconitine induced arrhythmia in guinea pigs or rats, adrenaline induced arrhythmia in guinea pigs and ligation of coronary artery of rats to induce arrhythmia. RESULTS Carvedilol 1 mg·kg -1 significantly reduced the chloroform induced VF incidence in mice<18 75% (3/16) vs 81 25%(13/16), carvedilol vs vehicle>. The effects were similar to which of propranolol. The doses of ouabain and aconitine to produce ventricular extrasystole (VE), ventricular tachycardia (VT), VF, cardiac arrest (CA) were significantly increased in 1 mg·kg -1 of carvedilol and of propranolol groups respectively ( P <0 01 vs vehicle). At the same dose, the effects of carvedilol on ouabain induced arrhythmia were greater than those of propranolol (P <0 01 vs vehicle, P< 0 01 vs propranolol). The duration of arrhythmia induced by 40 μg·kg -1 adrenaline were significantly reduced by carvedilol, in a dose dependent manner. Besides these, carvedilol also effectively reduced VT, VF, CA incidences and duration of VT in animals subjected to coronary artery ligation. CONCLUSIONS Carvedilol has antiarrhythmic effects in various animal models. At the same dose, 1 mg·kg -1 , its antiarrhythmic effects were at least equal to which of propranolol, or more potent. The antiarrhythmic effects provided by carvedilol may ultimately be beneficial to patients subjected to essential hypertension, coronary artery disease or congestive heart failure.