Mixed monolayers of thiol-terminated poly(ethylene glycol) (PEG) and thioacetyl GM1 glycolipid on Au(lll) were examined utilizing atomic force microscopy, infrared spectroscopy, and grazing incidence X-ray diffraction to determine the composition, structure, and morphology and to characterize the specific and nonspecific interactions with protein. These monolayer architectures are robust and are readily controlled to provide a network of receptor GM1 in the PEG-terminated matrix. However, we also find significant levels of nonspecific and nonnative protein binding that reader this simplistic model system unsuitable for highly sensitive biosensor device applications.