An enzyme-based amperometric biosensor was developed for the rapid determination of adenine in biological and food samples. Recombinant adenine deaminase (EC 3.5.4.2) from Schizosaccharomyces pombe was co-immobilized on graphite electrode with xanthine oxidase (EC 1.17.3.2), peroxidase (EC 1.11.1.7) and an Os mediator. Optimal working conditions were pH 7.0 and -150 mV vs. Ag/AgCl. The novel method was characterized by a detection limit of 1 mu M and a linear measuring range of 0.0050.1 mM. Different beer and tea samples were analyzed by the newly elaborated adenine biosensor. The results obtained correlate with the adenine content measured by the reference HPLC method.