Highly ordered TiO2 nanotube array with inner diameter of 120 nm was formed by anodizing titanium foils and was further modified for enzyme immobilization and biosensing. AuNPs sized in 8-12 nm were uniformly electrodeposited on TiO2 nanotube arrays by pulsed method. Glucose oxidase (GOD) was covalently immobilized on the surface of gold nanoparticles (AuNPs) modified TiO2 nanotube array electrode for the first time. Results demonstrate that the modified TiO2 nanotube array electrode exhibits good electrocatalytic performance and high sensitivity without any electron mediator. The covalently fabricated glucose biosensor shows higher immobilized ratio of GOD, good reproducibility and stability. These indicate AuNPs modified TiO2 nanotube array is an attractive material for using in the fabrication of biosensors because of its excellent biocompatibility, high specific surface area, unique nanostructure, and effective immobilization of biomolecules. This facile modification approach could be extended to prepare various TiO2 nanotube array based biosensors. (C) 2010 Elsevier B.V. All rights reserved.