Two series of zirconia supported molybdophosphoric acid (MPA) and MoOx (ammonium heptamolybdate as precursor) catalysts were synthesized with varying contents of MPA or MoOx (5-25 wt. %). The catalytic activity was evaluated for oxidative dehydrogenation of ethane (ODHE) to ethylene in a fixed bed catalytic reactor. The Mo oxide phases formed due to the decomposition of MPA during calcination were found to be more active for ODHE than the Mo oxides obtained directly from ammonium heptamolybdate precursor. BET surface areas and pore volumes are found to depend on Mo loading and varied in the range from 19 to 50 m2/g. XRD demonstrates the formation of Zr(MoO4)2 phase. FTIR confirmed the decomposition of MPA after calcination. Catalytic results revealed that the decomposed MPA/ZrO2 catalysts exhibited better performance compared to MoOx/ZrO2 solids with similar Mo contents. It has been observed that Mo loading has shown a clear influence on the catalytic activity and selectivity. Yield of C2H4 increased up to 15 wt. % MPA loading and then decreased with further increase in MPA content. Among all catalysts tested, the 15 wt. % MPA/ZrO2 exhibited the best performance.