The contribution deals with the development on the efficient Ni-alumina catalyst for the oxidative dehydrogenation (ODH) of ethane to ethene. The performance of Ni-alumina catalysts with varying nickel loadings and with thermal pretreatment was studied. We contribute to the understanding of the relationship between the activity of nickel species in ODH of ethane and its distribution. To analyze this effect, Ni-alumina catalysts were analyzed by UV-VIS spectroscopy, and H2-TPR profile. Ni-alumina catalysts were highly active and selective (ca. 80%) in the ODH of ethane. The catalysts contained both tetrahedral and octahedral nickel species, suggesting that nickel aluminate represented a partial spinel, where Ni(II) ions occupy both octahedral and tetrahedral sites of the oxygen lattice. It was suggested that the octahedral nickel species were more active than the tetrahedral ones.