Coprecipitated Co/Mg/Al2O3 catalysts were synthesised (Mg/Co/Al ratio 1:1:2 and 1:3:4) and characterised by TPR, TEM, XRD and BET. The materials catalysed the partial oxidation of methane to CO and H-2 (1:2 ratio) at 20 bar pressure (conversions of 75-95%). The catalyst deactivated with time on line (20% reduction in conversion in 150 min). BET analysis revealed that sintering of the catalyst occurred during the catalytic reaction. Further, large quantities of carbon were formed in the post bed part of the reactor. TEM analysis of the carbon revealed cobalt embedded carbon rods.