Different catalytic membranes containing V/MgO catalyst in a commercial ceramic support structure have been prepared. These membranes have been employed for the selective oxidation of butane to butene and butadiene. The effects of the vanadium concentration in the catalytic layer, the reactor configuration, the structural properties of the membrane and the operating conditions have been studied. The membrane reactor operating with segregated butane and oxygen feeds clearly outperforms (in terms of both selectivity and yield) the case of premixed feed on the same membrane. It is also shown that the structural characteristics of the membrane, (and in particular, the relative laminar and Knudsen contributions to permeation) have a strong influence on the reactor performance. Yields up to ca 20% have been obtained in this work.