The dehydrogenation of isobutane to isobutene in the presence and absence of carbon dioxide is discussed on the basis of catalytic studies. The V-Mg-O catalysts have been prepared using different preparation procedures. The structure and texture of the V-Mg-O catalysts were characterized by several techniques including X-ray diffraction (XRD), BET surface area measurements and infrared spectroscopy (IR). The results show that carbon dioxide enhances isobutane conversion in the reaction carried out over the V-Mg-O catalyst prepared by citrate method.