The ability of excimer lasers to modify the surface morphology and the electrical conductivity of polymers with spatial resolution on a nanometer scale has been demonstrated. Using holographic techniques with a KrF excimer laser, periodic line structures with periods ranging from 166 to 950 nm have been ablated into polyimide (Kapton) and polybenzimidazole (PBI). The nonlinear nature of laser ablation allows linewidths as small as 30 nm to be obtained, exceeding the resolution expected from linear optics. These experiments establish a new spatial resolution limit for laser ablation and illustrate the dependence of resolution on material properties. This technique has been combined with the ability to modify the electrical conductivity of polymers to produce an array of permanently electrically conducting wires in polyimide with a 0.5-μm width and a 0.9-μm period. The electrical conductivity of these submicrometer wires was greater than 1 Ω-1 cm-1.