A single-walled carbon nanotube (SWNT)-based enzymatic glucose/O-2 biofuel cell with a high voltage is demonstrated. The fuel cell uses glucose dehydrogenase as the anode biocatalyst for the oxidation of glucose, and laccase as the cathode biocatalyst for the reduction Of O-2 (see figure). The SWNTs are used as electrode materials, as a support for electrocatalysts and biocatalysts, and for facilitating the direct electron transfer of laccase.