The miniaturized polysilicon electrodes for conductometric sensors have been fabricated by standard CMOS process. The interface impedance of polysilicon and saline solution (0.9% NaCl) are measured in the frequency range of 100 Hz-1 MHz. At this frequency range, the impedance can be described as K/(i omega)(beta), where K is around 33 M Ohm Hz(0.9)3 and beta is about 0.93 for the electrode area of 2 mm(2). Compared to Pt black and Pt electrode, the impedance of polysilicon electrodes is quite large. This is supposedly due to the formation of silicon oxide laver at the surface of polysilicon electrodes in saline solution. The response of a pair of polysilicon electrodes to 0-75 mM KCl in saline solution at 20 kHz has good linearity. With the deposition of urease on the top of the pair of polysilicon electrodes, it is also possible to detect urea concentration with this conductometric setup.