Polypyrrole (PPY) and PPY/SBA-15 host-guest composite materials have been prepared using chemical synthesis route and characterized by XRD, IR, N-2 adsorption-desorption isotherms, and SEM. The humidity sensitive properties (HSP) of this kind of materials have been studied by analyzing the variation curve of impedance as a function of relative humidity. It was found that the PPY/SBA-15 host-guest composites materials exhibit better HSP than that of the corresponding pure PPY. (c) 2006 Wiley Periodicals, Inc.