The activity and selectivity of the catalysts used in oxidative dehydrogenation of alkanes results from a combination of factors related to the nature of the catalysts and to the operating conditions under which these are used. In this work, the oxidative dehydrogenation of alkanes (mainly butane) over V-Mg-O and VOx/Al2O3 catalysts has been studied. The investigation is focused on the examination of the oxidation and reduction processes that take place on the surface of both catalysts. A combination of catalyst characterization and kinetic measurements has been used, in an attempt to relate the rate of these redox processes to the catalytic performance observed under oxidative dehydrogenation conditions.