The kinetics of glucose electrooxidation on different catalysts has been studied at physiological conditions (pH 7 and 37 0C). Electrochemically activated rough gold, rough gold modified with a self-assembled monolayer (SAM) of cystamine and an enzymatic electrode based on a charge transfer complex (CTC) and glucose oxidase (GOx) have been tested. The influence of glucose concentration, electrode rotation rate and presence of oxygen has been investigated and the stability of the different catalysts has been evaluated. All parameters have been discussed in the context of the potential application of these catalysts in an implantable glucose/O2 biofuel cell. Rough gold exhibits high activity with very low overpotential for glucose oxidation but its extreme instability and low oxygen tolerance make it inappropriate as potential anode in a biofuel cell. The CTC enzymatic electrode on the other side shows high activity for glucose oxidation, reasonably low overpotential and relatively high stability.