We report the integration of organic electrochemical transistors with a surface-directed microfluidic system. The end product is a chip in which an analyte solution is distributed in four separate measurement reservoirs, each containing a transistor that uses the analyte as an integral part of its device structure. The use of a surface-directed microfluidic system enables the distribution of the analyte solution without the application of external pressure. The use of this chip in the detection of multiple analytes is demonstrated.