The catalytic oxidation at atmospheric pressure of very lean homogeneous mixtures of hydrogen with air was investigated in a specially developed catalytic packed bed tubular reactor using a binary cobalt oxide/chromium oxide catalyst. A platinum catalyst was also used for comparison. A wide range of equivalence ratios and different flow velocity values were considered. It was found that a certain binary combination of these catalytic metallic oxides that was optimized for the oxidation of methane was also very effective in the oxidation of hydrogen and hydrogen-methane mixtures in air. It was found that at least 50% of hydrogen conversion occurred at around 75degreesC and full conversion at 125degreesC. This compared reasonably well with the corresponding temperature levels for the same operating conditions when platinum was the catalyst. It was also found that the addition of hydrogen at such low temperatures did not enhance the conversion rate of methane within hydrogen-methane mixtures. (C) 2003 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.