A 10-year old male mongrel dog was presented to the University Veterinary Teaching Hospital with a two-month history of episodic syncope. Twenty-four hr Holter electrocardiographic (ECG) recording revealed frequent episodes of advanced atrioventriculer block with long periods of ventricular asystole. The cause of syncope was determined to be Adams-Stokes syndrome exhibited bradyarrhythmia. After the animal failed to respond to medical therapy, permanent transvenous pacemaker implantation was performed. Postoperative Holter ECG showed 100 beat per min programmed pacemaker rhythm, which indicated successful capture of the artificial pacing. The dog recovered smoothly from the operation and syncopal episodes completely disappeared. Six months after the surgery, no complications were observed and the dog's quality of life has dramatically improved.