A series of V2O5/Al2O3 catalysts with fixed V2O5 content (10 wt %) but varying Al2O3 supports were prepared by impregnation technique and tested for the oxidative dehydrogenation of ethane (ODHE) to ethylene in a fixed bed quartz reactor in the temperature range from 500 to 600 degrees C. The nature of alumina support applied had a significant influence on the catalytic performance. Among all alumina supports investigated, the high surface area gamma-Al2O3 (200-300 m(2)/g) supported V2O5 catalyst showed the best performance in ODHE with selectivity to ethylene of ca. 45-50%. This result is mainly due to the high dispersion of vanadia species on the support surface. On the other hand, low surface area alpha-Al2O3 (5 m(2)/g) and ?-Al(2)O3 (<100 m(2)/g) supported catalysts exhibited much higher ethane conversion under the same reaction conditions, but they also exhibited low selectivity to ethylene because of the existence of larger V2O5 crystallites. In addition, a structurally disordered gamma-Al2O3 (ca. 6 m(2)/g) containing a high proportion of penta-coordinated Al-sites was also included in the present study. Amazingly, this low surface area alumina supported V2O5 catalyst displayed a good performance in ODHE. Such behavior can be ascribed mainly to the presence of the penta-coordinated Al surface sites acting as anchors for preferentially monomeric and oligomeric VOx species leading to a prime dispersion. Therefore, performance similar to that of the high surface area aluminas was reached.