We improved adhesiveness of a neuron-like cell, PC12, on a Parylene-C surface by 02 plasma treatment which changes the surface from hydrophobic to hydrophilic. Neural cell adhesiveness on the plasma-treated Parylene-C was more than twenty times better compared to non-treated Parylene-C and it was close to that on a conventional polystyrene tissue-culture dish. (C) 2011, The Society for Biotechnology, Japan. All rights reserved.