Alumina-stabilized nanosized rutile Mo-V-Nb-O oxide phases are prepared, characterized and used for the selective oxidation of propane to acrylic acid. Coverage on alumina support, atomic Mo/V molar ratio and calcination conditions (inert vs. oxidizing) affect the structure and catalytic performance. The effect of Mo/V ratio is opposite depending on calcination atmosphere. Segregated molybdenum oxides are not efficient while partially reduced rutile-type mixed molybdenum-vanadium oxide phases are efficient for the conversion of propane to acrylic acid. Niobium species would have a structural effect, stabilizing mixed molybdenum-vanadium oxide phases. (C) 2009 Elsevier B.V. All rights reserved.