Diamine oxidase (DAO) from Porcine kidney E.C. 220.127.116.11 is used for the amperometric detection of biogenic amines. Immobilization of enzyme is performed via entrapment in conducting poly (3,4-ethylenedioxythiophene) during electrochemical polymerization. The responses of the enzyme electrodes are measured via monitoring current at +0.7 V. In order to minimize the common interferences, an over oxidized film of polypyrrole is introduced to the electrode. Thickness of the film, kinetic parameters, substrate specificity, storage stability, pH were investigated. In spite of very low activity of the commercial DAO, the biosensor displayed high response in flow experiments, short response time, a good linear response and low detection limit and excellent anti-interference characteristics.