Semiconductor nanowires are being actively investigated because of their unique physical properties and potential applications in nanoelectronics and optoelectronic devices. However, current hurdles for device integration include the lack of control over the orientation, location, and packing density of nanowires. This communication presents for the first time the use of a unique, bottom-up approach for the catalyzed growth of semiconductor nanowires via biological templating. High-density, vertically oriented growth of Ge nanowires with monodispersed diameters and spacings was achieved through patterning of very small sized (5-20 nm) Au nanoparticles using bacterial surface-layer proteins as a template. We envision the applicability of this biotemplating approach to a variety of nanowires and substrate materials.