A guide wire having a non-metallic, non-woven core wire is disclosed. Monofilar, polymeric fibers of multifilar helically-wound non-metallic fibers are preferred core wire materials. The guide wire optionally includes further coatings and other materials on the core wire. In one embodiment, a non-metallic distal coil wire is disclosed. The guide wire of this invention is particularly useable for magnetic resonance imaging applications.