Methane-to-CO and H-2 conversion reactions, involving partial oxidation by O-2, oxy-steam reforming, oxy-CO2 reforming, CO2 reforming, simultaneous steam and CO2 reforming, over a NiO-MgO solid solution(Ni/Mg = 0.5)have been investigated. The calcination (up to 1200 degrees C) temperature of the catalyst has a small but significant effect on its activity/selectivity in the oxidative conversion of methane to syngas. The reduction (by H-2 temperature of the catalyst has no significant effect on the catalyst＇s performance. The catalyst shows high activity and selectivity in the oxy-steam reforming and oxy-CO2 reforming reactions, at 800-850 degrees C and high space velocity [(40-50)x10(3) cm(3) g(-1) h(-1)]. These two processes :involve coupling of the exothermic oxidative conversion and endothermic steam or CO2 reforming reactions, making both the processes highly energy efficient and also safe to operate. The catalyst also shows high methane conversion activity (nearly 95% conversion) with 100% selectivity for both CO and H-2 in the simultaneous steam and CO2 reforming of methane at (800-850 degrees C) at a high space velocity (3.6x10(3) cm(3) g(-1) h(-1)).