Carbon fibers are a superior reinforcement for composite materials because of their excellent mechanical properties and their low density. A knowledge of the surface of these fibers down to the nanoscale is of great value because the interfacial bonding to the fiber surface has a considerable influence on the mechanical properties of the composite. In this study, the surfaces of as-received carbon fibers were characterized by scanning tunneling microscopy while the surfaces of carbon fibers coated with a silica deposit were observed with an atomic force microscope. In addition, chemical and physical adsorption techniques were used to characterize the global surfaces of the fibers. The data from these various techniques were correlated with silica deposition rate data to produce a model for the nucleation and deposition of silica on carbon fibers.