Catalytic activity of LnOX (Ln = Sm, La or Nd; X = Cl or Br) and Ln(1-x)Lm(x)OX (Ln = La and Lm = Pr, 0 less than or equal to x less than or equal to1) catalysts has been studied using a continuous flow reactor system. Methane oxidation using LnOX results in an increase of CO2 selectivity in the order Nd > La > Pr > Sm, while using Ln(1-x)Lm(x)OX systems CO2 selectivity is enhanced by increasing partial lanthanum substitution with praseodymium. A decrease in CO and Ct hydrocarbons selectivities is also observed at isoconversion. The different compounds structures studied do not change with time under reaction conditions within the temperature range at which the catalysts are stable.