In this paper we have described that multi-walled carbon nanotubes (MWNTs) can be homogeneously dispersed and solubilized in water using non-covalent functionalization. These soluble MWNTs were then used for the immobilization of glucose oxidase (GOx) on glassy carbon electrode. Scanning electron microscopy is used to investigate the nanoscale structure of the film formed by the functionalized MWNTs. Electrochemical measurements were conducted to reveal the electroactivity of the GOx on the MWNT modified electrode. The functionalized MWNTs served as a network carrier for GOx as well as a conductor, enhancing greatly the response current. The GOx immobilized in this way retained its bio-electrocatalytic activity for the oxidation of glucose. (C) 2010 Elsevier BM. All rights reserved.