Aligned multi-walled carbon nanotube (ACNT) arrays synthesized on stainless steel plates were applied to a glucose (Glc) biofuel cell with glucose oxidase (GOx). The ACNT showed no direct electron transfer with GOx; however, large electrocatalytic current of 0.68 mA cm(-2) at 0.6 V vs. silver-silver chloride saturated KCl was observed with a mediated electron transfer (MET) type electrode when p-benzoquinone was used as a mediator. An assembled single cell with the MET type anode and an oxygen reduction cathode by platinum showed an OCV of 0.57 V and a maximum power density of 100 mu W cm(-2). (C) 2015 The Electrochemical Society. All rights reserved.