The characteristics of an inexpensive transistor-based chemical sensing platforms with organic polymer, polyaniline (PANI), was investigated in terms of tranconductance, pH sensitivity, and drift properties. The platform consists of a printed circuit board manufactured in a standard manufacturing process and commercial discrete MOSFETs. The platform is funtionalized with PANI by a simple low-cost drop casting. The platform shows low average pH sensitivity of 9.1 mV/pH in the range 4–7 where physiological recognition events take place and as such is a promising candidate for intrinsic charge-based biosensing since PANI is able to directly interact with charged macromolecules such as proteins and DNA. In addition, the PANI functionalized sensors show low nonmonotonic drift and only slightly reduced transconductance compared with the MOSFET counterpart.