Mesoporous　SBA-15　and　1-12　wt%　CrOx/SBA-15　have　been　prepared　by　triblock　copolymer　P123-templated　hydrothermal　synthesis　and　incipient　wetness　impregnation　method,　respectively.　The　materials　were　characterized　by　means　of　a　number　of　analytical　techniques　and　their　catalytic　activities　were　evaluated　for　the　oxidative　dehydrogenation　(ODH)　of　isobutane.　It　is　found　that　with　rise　of　chromia　loading,　the　morphology　of　SBA-15　changed　from　long　interconnected　chains　to　short　banana-like　rods,　and　finally　changed　to　spheres　with　wormholes.　The　results　of　Raman　and　X-ray　photoelectron　spectroscopic　investigations　reveal　that　the　surface　Cr　species　are　mainly　Cr6+　in　mono-　and　polychromate,　with　a　minor　amount　of　Cr3+　due　to　alpha-Cr2O3　formation.　The　H-2　temperature-programmed　reduction　study　demonstrates　that　the　catalysts　at　chromia　loading　of　6-10　wt%　are　more　reducible.　The　10　wt%　CrOx/SBA-15　catalyst　exhibits　the　best　activity,　showing　79%　C-4-olefin　selectivity　and　11%　C-4-olefin　yield　at　540　degrees　C.　One　monolayer　CrOx　coverage　on　SBA-15　occurs　at　Cr　surface　density　=　1.05-1.43　Cr-atom/nm(2).　We　conclude　that　factors　such　as　(i)　presence　of　active　Cr6+　in　mono-　and　polychromate,　(ii)　strong　redox　ability　of　Cr　species,　and　(iii)　good　dispersion　of　CrOx　on　banana-like　rods　of　well-ordered　mesoporous　SBA-15　are　responsible　for　the　good　performance　of　the　SBA-15-supported　chromia　in　isobutane　ODH.　(C)　2008　Elsevier　B.V.　All　rights　reserved.