A novel sol-gel route has been developed to prepare silica supported Ni and Co molybdate catalysts. The metal oxides obtained are homogeneously dispersed in the silica matrix and specifically for NiMoO4 the high-temperature beta-phase which is catalytically more active has been found to be stable at room temperature. The catalytic activities of the silica supported stoichiometric Ni and Co molybdates prepared by sol-gel method have been tested continuously in the oxidative dehydrogenation of isobutane.