Organic/MoO3 nanohybrid thin films have been successfully prepared by an ex-situ intercalation process. The host MoO3 films were first deposited on LaAlO3 (LAO) single crystal substrates by using a CVD method followed by the intercalation of butylammonium ions, (BuNH3)+, into the MoO3 films to give (BuNH3)xMoO3 thin films. The preparation of highly b-axis oriented MoO3 films is crucial to prepare the (BuNH3)xMoO3 films. The (BuNH3)xMoO3 thin films exhibit a resistance-increasing response to aldehyde gases as in the case of bulk samples, whereas no response was observed for methanol, ethanol, chloroform, acetone, toluene, and xylene. The thin film process developed for intercalative organic-inorganic hybrid makes it possible to apply this material in VOC sensor devices.