Results are presented of an experimental laboratory investigation of the oxidation reactions of heated low velocity streams of homogeneous lean fuel-air mixtures within a packed bed tubular reactor at atmospheric pressure in the presence of non-noble metal oxides catalysts. The main fuel considered was methane, however, other common gaseous-fuels, i.e. propane, carbon monoxide, hydrogen and ethylene were also examined for comparative purposes. It was shown that binary cobalt oxide/chromium oxide catalysts can be effective in the oxidation of very lean fuel-air mixtures. Furthermore, there is an optimum value of their mass ratio that could produce a significant improvement to the low temperature oxidation of the lean mixtures examined and the corresponding resulting emissions.