A novel, stabie, and all-solid-state miniaturized reference electrode (MRE) prepared by changing the properties of a conductive polymer for potentiometric applications is presented in this study A monomer of a conductive polymer, pyrrole, was electrodeposited to form polypyrrole on an indium-tin oxide (ITO) glass at a DC power of 5 V The difference of the solid-state MRE from the Ag/AgCl glass reference electrode is that the former requires no inner electrolyte and can be preserved without any storage solution (such as saturated KCI solution). In this study, the potentiometric characteristics of the solid-state MRE are investigated using the current-voltage (I-V) measurement system The solid-state MRE exhibits sufficient stability and reproducibility in acid-base: sodium chloride and potassium chloride solutions Furthermore. the solid-state MRE can collocate successfully with H(-)-, Na(+)-, and K(+)-ion selective electrodes to measure H(+), Na(+), and K(+) ion concentrations in acid-base, sodium chloride, and potassium chloride solutions, respectively (C) 2009 The Japan Society of Applied Physics