The purpose of this study is to prepare the thin film of C-type parylene (C-type polyxylylene, parylene-C) with improved biocompatibility for the biomedical applications, since in spite of the popularity, the parylene-C has been known to have the less biocompatibility than the N-type or D-type parylene. To prepare the well-designed parylene films through the chemical vapor deposition (CVD) process and the subsequent plasma surface treatment, the parameters of deposition and surface modification were controlled to obtain optimized physical and surface properties. Using CVD, the thin films of parylene-C as thick as 5 mu m were prepared under different deposition pressures. When increasing the deposition rate of parylene film or the deposition pressure, the tensile strength of film increased, whereas the properties such as the surface contact angle and permeability, and the elongation decreased. The deposition rate could be controlled to optimize the physical and physiochemical properties of films. The hydrophilicity of the parylene-C film increased after plasma Surface treatment by showing the larger water contact angle than untreated one. When the radio frequency power was above 100 W in the plasma process, the thin film obtained reveals an excellent cytotropism. It shows the improved biocompatibility with living cells. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 3677-3685, 2009