Standard Gianturco and "mini" coils cannot be used with some of the present microcatheter systems. However, occasions arise in which metallic coils would be an ideal embolic agent in vascular structure accessible only to a tracker (2.2-French) catheter system. We performed nine embolization procedures in eight patients with arteriovenous fistulas using platinum coils as an embolic agent. Fistulas were completely occluded in six of the nine cases. In several cases, platinum wire embolization was augmented with other agents. Complications occurred in two cases, neither resulting in permanent neurologic deficits. Advantages of using platinum coils included availability, radioopacity, thrombogenicity, biocompatibility, and delivery through microcatheters, specifically the tracker catheter system.