In this paper, we report the initial response of 3T3 fibroblast and MG63 osteoblast cells to engineered nanotopography gradients of three nanoparticle diameters (16 nm, 38 nm and 68 nm). These nanoengineered surfaces were designed to provide a range of nanoparticle densities and comparable surface area across the gradients of different nanoparticle sizes. Importantly, we provided a uniform surface chemistry in order to be able to examine the effect of pure surface nanotopography. We found that nanotopography features of 16 nm encourage the adhesion of both cell types and that there is a critical nanoparticle density between 50 and 140 particles per μm2 where cells adhered in the greatest numbers. When nanotopography features increased to 38 nm the 3T3 cells adhered and spread well, however, the MG63 cells adhered and spread poorly. Both cell types adhered in lower numbers when the nanotopography feature size increased to 68 nm. This work demonstrates that there is a specific nanotopography scale that encourages cell adhesion and spreading, however, the preferential lateral spacing and height of the nanotopography is different for different cell types.