Self-assembly of 100 mu m spheres on a patterned electrode under the influence of an applied electric field is demonstrated. This process occurs for ordered arrays and arbitrary patterns, over areas up to similar to 0.7 cm(2), with a defect rate (e.g., missing spheres or extra spheres, circled in Figure) of about 1 %. These arrays of microspheres can be transferred into polymeric matrices, such as poly(dimethylsiloxane), polyurethane, and epoxy.