Protein interaction with surfaces is one of the most important criteria for the selection of implantable biomaterials as it can mediate further cellular interaction and therefore influence biocompatibility of the surfaces. An ideal biomaterial would adsorb no protein, which is practically impossible to achieve. Here we have demonstrated that control of protein adsorption can be achieved by modifying silicon surfaces with a biocompatible polymer like poly(ethylene glycol) (PEG). Two different methods to modify the silicon surface were used. Two model proteins, namely, fibrinogen and bovine serum albumin, were used to study the adsorption on PEG-modified surfaces. The adsorbed protein was characterized using fluorescence microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy.