The adherence and viability of neural cells (primary cortical cells) from rat embryo on silicon wafers with varying surface roughness (10 to 250 nm) at the nano scale were investigated. The roughnesses were achieved by using chemical etching. Atomic force microscopy was utilized to determine surface roughness. We examined the adherence and viability of neural cells by using scanning electron microscopy and fluorescence immunoassaying. Antineuron-specific enolase antibody was used for immunostaining. Results from this investigation show that for these specific neural cells, there is an optimum surface roughness range, R(a) = 20 to 100 nm, that promotes cell adhesion and longevity. For silicon-based devices, this optimum surface roughness will be desirable as a suitable material/neuron interface.