Poly(3,4-ethylenedioxythiophene) (PEDOT) and its derivatives are relatively new, and unique members of conducting-polymers family. In this article, we present an approach for simple, reliable and cost-efficient electrochemical biosensor for real-time detection and quantification of phenolic compounds (PhCs). The PEDOT: poly(styrene sulfonate) (PSS) polymer, directly screen-printed on the surface of the working electrode, was shown to act as an effective electrical conductor but also as an efficient redox mediator. It has also been found suitable for the reduction of quinone ions at low reducing potentials, close to 0 V versus Ag/AgCl, thus minimizing interferences due to other electroactive species present in real samples. Based on these properties, a biosensor based on tyrosinase immobilized on PEDOT: PSS-modified electrodes was developed allowing the detection of PhCs in surface waters. The biosensor displayed very good performance in terms of sensitivity, detection limit and linear range. Assays using surface water previously spiked with bisphenol A showed that the biosensor was able to detect PhCs in real conditions with no matrix effect. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 50: 2286-2292, 2012