Oxidative dehydrogenation (ODH) of ethane and propane feeds has been examined under a variety of temperatures, flow rates, and gas compositions in a fixed bed reactor using boron nitride-based catalysts either promoted with various metal oxides or supported on silica. Tests performed at low conversion in the presence of a large amount of N-2 diluent indicated that addition of MgO to boron nitride (BN) led to similar to 10-fold increase in alkane conversion, with a drop in the C-2-C-3 olefin selectivity from 90% to 79%. Testing using concentrated feeds with small amounts of diluent (3%) indicated that metal-oxide promoted BN catalysts could maintain C-2-C-3 olefin selectivities as high as 65% at high alkane conversion (similar to 60%). Catalyst productivity values under these conditions approached 16 kg(olefins) kg(cat)(-1) h(-1). Under nondilute conditions, the catalysts appear to act as initiators of radical reactions at the surface, after which the radicals desorb into the gas phase and undergo propagation steps.