PURPOSE: To establish the method of constructing an experimental aneurysm model in porcine carotid artery. MATERIALS AND METHODS: Fourteen aneurysms were created in the carotid arteries of eight pigs. After paramedian incision under intravenous anesthesia, the common carotid artery and external jugular vein were separated. A portion of the latter was cut to make an aneurysmal sac and this was sutured to the side wall of the common carotid arterial wall (end to side). Within one week, an arteriogram was obtained in all pigs and color Doppler study was performed in four. Digital subtraction arteriograms were serially obtained three images/sec, and these were analyzed to determine the size of the sac and the neck, flow pattern in the aneurysm, and stenosis in the common carotid artery. RESULTS: Arteriographic findings were obtained in ten of 14 aneurysms. Six aneurysms were saccular in shape, and the mean size of the sac and neck was 16x10 mm and 5.3 mm, respectively. Four aneurysms were lobulated, and in these cases, the mean size of the sac and neck was 9x3 mm and 3.7 mm, respectively. The mean size of the proximal common carotid artery was 4.5 mm, and at the operation site, mean stenosis was 40%. CONCLUSION: In 10/14 cases (71%), we successfully established an aneurysm model in the porcine carotid artery, and believe that it is suitable for use in interventional neuroradiology experiments.