The successful covalent linking of green fluorescence protein and streptavidin to patterned benzophenone-modified boron-doped diamond (BDD) electrodes is demonstrated. Photoreactive benzophenone moieties were covalently grafted to oxidized diamond surfaces via an esterification reaction. Patterned BDD surfaces were obtained using a UV/ozone lithographic approach either on hydrogen-terminated. BDD or on poly(ethylene)-glycol-modified BDD surfaces. UV light (lambda = 365 nm) irradiation of the patterned BDD surfaces in the presence of green fluorescence protein (GFP) or streptavidin resulted in the covalent immobilization of the proteins. The presence of poly(ethylene) glycol chains reduces significantly the nonspecific adsorption of the proteins. The success of the photoimmobilization of streptavidin was evidenced through biomolecular interaction with avidin. The preservation of the biological activity was furthermore underlined by photoimmobilization of peptides directly onto benzophenone modified BDD using a photomask.