A mechanical vascular occluder was studied in eight pigs to test its efficacy in arteries of different diameters, stability over time, and safety in placement. The main component is a self-expandable spindle made of tubular stainless steel mesh. Simple steel spindles, double spindles, and Dacron-core spindles were placed in the common carotid artery, main renal artery, renal artery branches, and infrarenal aorta. Follow-up arteriograms were obtained immediately, 30-60 minutes, and (except for aortic spindles) 7 days after deployment. The left common carotid artery was occluded in all pigs, regardless of spindle type. In the main renal artery and its branches, simple steel spindles did not achieve complete occlusion. Double and Dacron-core spindles produced immediate occlusion without recanalization on the 1-week follow-up arteriogram, except for one spindle with an incomplete Dacron core and two spindles that did not completely fill the arterial lumen. Two Dacron-core spindles achieved immediate complete occlusion of the infrarenal aorta. No migration was seen with any spindle.