The use of biomolecules in the creation of inorganic materials offers an alternative to conventional synthetic methods. Biomolecules are currently used to control nucleation and growth of inorganic nanoparticles. Here we demonstrate the formation of silver nanoparticles in the presence of silver-binding peptides. Examination of the silver nanoparticles by transmission electron microscopy revealed a variety of crystal morphologies such as hexagons, triangles and spheres. The peptides serve to reduce the silver ions in the aqueous solution to metallic silver as well as control crystal growth. The nucleation property of peptides can be used as tool for bottom-up fabrication.