Fistulas were surgically created between the carotid artery and jugular vein in dogs. They were successfully occluded by means of transcatheter placement of stainless steel coils with attached woolen strands. Angiographic studies performed prior to, immediately after, and 4 weeks after occlusion were used to evaluate the efficacy of the procedure. Specimens excised 4 weeks after occlusion revealed fibrotic encasement of the coil in the fistula, forming a permanent occlusion. The technique has clinical application, and suggestions concerning its clinical use are presented based on information gained from the animal study.