The work is aimed at study of quasi 1-D silicon nanostructures (nanowires) adsorption properties via electrical impedance spectroscopy. Nanowires were synthesized by cryogen plasma chemical etching and transferred to auxiliary substrate with interdigital gold contacts. Further, nanowires were exposed to air, unsaturated vapors of ammonia and hydrochloric acid aqueous solutions with concentrations about 0.1–1.0 mmol∙l–1 followed by measurement of the nanowires impedance spectra. Changes in the impedance spectra of nanowires upon exposure under analyte vapors are considered in terms of a correlation between the adsorption properties of nanowires and their electrical characteristics.