Poly(tetrafluoroethylene) (PTFE) is a material that causes only a few rejections in a living body but has low tissue affinity. A soft tissue implant material that not only has high biocompatibility but also excellent bondability has been developed by photo-chemically incorporating OH functional groups on the PTFE surface with ArF excimer laser irradiation. Protein adsorption on untreated and treated samples was evaluated by scanning electron microscopy (SEM) and attenuated total reflection Fourier-transform infrared (ATR-FT-IR) spectroscopy, with bovine serum albumin (ALB) and fibrin (FIB) solutions. It has been found that protein adsorption increases with the increase in the OH group density on the PTFE surface. The maximum adsorption of both ALB and FIB was found on the PTFE sample treated with a laser fluence of 20 mJ/cm(2) and a shot number of 2000, whose water contact angle was 28 degrees; the quantities of both ALB and FIB adsorbed increased by a factor 2 as compared with untreated sample.