Degradations of the adhesive proteins of gelatin (GEL), laminin (LN) and poly-D-lysine (PDL) on polystyrene (PS) by carbon negative-ion implantation for nerve-cell adhesion patterning were investigated. Solutions of adhesive proteins were in the concentration ranges of 5 – 1000, 0.5 – 50 and 0.5 – 33 g/ml for GEL, LN and PDL, respectively. The ion implantation conditions were set at 10 keV and fluences of 1014 – 1016 ions/cm2. Based on XPS analysis, the suitable protein concentrations for coating the pre-treated PS with C¯-implantation at 10 keV and 3×1015 ions/cm2 were in the ranges of 5 – 1000, 2.5 – 50 and 5 – 33 g/ml for GEL, LN and PDL, respectively. After C¯-implantation into the protein-coated PS with concentrations, amounts of proteins left on PS were evaluated by XPS. Amount of all proteins decreased with an increase in the ion fluence. After in vitro cell culture, the cell-adhesion patterns on the unimplanted regions of GEL-coated PS at 5 µg/ml and LN-coated PS at 2.5µg/ml for rat adrenal pheochromocytoma cell (PC12h) and that on the unimplanted region of PDL-coated PS at 5 µg/ml for rat embryonic brain cortex neuronal cells were obtained at ion implantation fluence of 1014 ions/cm2.