MeAPO-5 (Me = V, Co, Mg) and MeVAPO-5 (Me = Co, Mg) were prepared by hydrothermal synthesis and they were characterized by N-2 adsorption, XRD, FTIR of piridine adsorption/desorption, TPR and UV-visible spectroscopy. For comparative purpose, MgO- and Al2O3-supported vanadium catalysts were also prepared. Their catalytic properties for the oxidative dehydrogenation (ODH) of ethane and the oxidation of cyclohexane were studied. The ODH of ethane was studied, at atmospheric pressure, in the 500-600 degrees C temperature interval, with an ethane/oxygen/helium molar ratio of 4/8/88. The oxidation of cyclohexane was studied at 125 degrees C and an oxygen pressure of 10 kg/cm(2). Different catalytic behaviour was observed depending on the transition metal incorporated, the catalyst structure and the reaction studied. The importance of the redox and the acid character of the catalysts on their catalytic properties is discussed.