This paper presents a miniaturized potentiostat readout circuit patch developed for electrochemical or biosensors. The presented patch has been fabricated on a flexible polyimide substrate using off-the-shelf electronics. In contrast to the traditional bulky equipment for electrochemical analysis, the presented patch is conformable and portable. As a proof of concept, the system has been used for pH measurements in buffer solution (6- 8 pH values) with a printed thick film potentiometric pH sensor having platinum counter electrode. The obtained results are in line with a commercially available potentiostat that has been used for benchmarking.