Conducting polypyrrole microtubules have been prepared by template synthesis inside track-etch membranes. The interiors of these microtubules can adsorb the redox enzyme, glucose oxidase. The enzyme-coated tubules have been employed in the construction of a third generation amperometric biosensor for the determination of glucose. With this biosensor, glucose concentrations in the range 0.1-250 mM can be measured easily. The polypyrrole microtubules have been characterized by different microscopic techniques, including scanning tunnelling microscopy. Based on the microscopy data, a model is presented for the interaction between the conducting polymer and the glucose oxidase molecules.