Oxidative dehydrogenation catalysts comprising MoVNbTeO having improved consistency of composition and a 25% conversion of ethylene at less than 420° C. and a selectivity to ethylene above 95% are prepared by treating the catalyst precursor with H2O2 in an amount equivalent to 0.30-2.8 mL H2O2 of a 30% solution per gram of catalyst precursor prior to calcining.