The authors have investigated the formation of block copolymer nanocavities on H-terminated conducting Si(111) surfaces as templates for the electrochemical growth of perpendicular metallic nanowire arrays. Poly(styrene)-block-poly(methyl methacrylate) block copolymers (PS-b-PMMA) of appropriate block length and PS to PMMA ratio were used to create a self-assembled array of perpendicular nanocavities in which the PS majority phase is continuous and surrounds cylinders of the minority PMMA phase. Here, we report that H-terminated conducting Si(111) surfaces are also capable of inducing a perpendicular orientation in block copolymers, which—in all likelihood—is a direct result of the H-termination (i.e., removal of the oxide layer). Atomic force microscopy reveals that an acetic acid wash of the annealed block copolymer causes the minority PMMA component to be rearranged, giving rise to cavities that are perpendicular to the conducting Si substrate. Subsequently, scanning electron microscopy reveals that electrodeposition into the nanocavities can be achieved, producing an array of metallic nanopillars, 20 nm in diameter.