Gas sensor with high molecular selectivity is highly demanded in many fields of industry or disaster relief. Molecularly imprinted polymer (MIP) can recognize target gas by specific adsorption for template molecule. In this study, a novel chemiresistor, gas sensor which combined with MIP and conductive nanoparticles has been developed. The gases were distinguished based on molecularly structure by MIP. If gas molecule is absorbed into this polymer, structures and properties of conductive composites are changed. It causes electric resistance changed. It is conceivable that the degree of resistance change is dependent upon the amount of absorption. Moreover, MIP absorbs larger quantity of template molecule than similar gas molecule. So this MIP chemiresistor can be used for measurement of specific target gas based on magnitude of response. Measurement results of gas sensing showed that larger response was produced by MIP chemiresistor for the template molecule than other gas and NIP (non-imprinted polymer) composite. It means that a sensor which could both recognizing molecules and transduce electrical signal simultaneously was successfully developed.