Materials to enhance cell adhesion were synthesized by surface integration of peptide, Arg-Gly-Asp-Ser(RGDS), which is an active-site sequence of cell-adhesive proteins. Polystyrene film was glow-discharged and graft-copolymerized with acrylic acid. Then the peptide was immobilized to the poly(acrylic acid) grafts by using water-soluble carbodiimide. The cell-adhesive activity of the RGDS-immobilized film increased with increasing amount of immobilized peptide, and approached the activity of fibronectin(FN)-immobilized film. The RGDS-immobilized film was more stable against heat treatment and pH variation than the FN-immobilized film. In addition, the RGDS-immobilized film enhanced cell growth more strongly than the FN-immobilized film.