A series of alkali metal halides/ZnO(60 wt.-%)/alpha-Al2O3 and NaCl/MnO2 were tested far the oxidative coupling of methane to ethylene and ethane. Sodium halides such as NaF, NaCl, NaBr and NaI were used as alkali metal halides. Recorded activities were associated with the apparent molal enthalpy of formation of sodium halides. The activity order was NaBr > NaCl > NaI > NaF. NaCl and NaBr played a role as promoters. NaF and NaI played a role as inhibitors. A kinetic study showed the reaction over NaCl(30 wt.-%)/ZnO(60 wt.-%)/alpha-Al2O3, was of the dual site Langmuir-Hinshelwood type. The obtained activation energy for the methyl radical formation was ca. 39 kcal/mole. The active oxygen species responsible for methyl radical formation seems to be a diatomic oxygen such as O-2(2-) or O-2(-) adsorbed on the surface of the catalyst.