Electrochemical oxidation and determination of glutathione (GSH) were investigated with well-aligned carbon nanotube (CNT) arrays. Square wave voltammetric and amperometric results suggest that aligned-CNT electrode exhibits excellent electrochemical activity and good anti-fouling property for direct electrochemical oxidation of glutathione. Also, the preliminary application of the aligned-CNT electrode for amperometric determination of glutathione was evaluated. (c) 2005 Elsevier Ltd. All rights reserved.