Steam reforming of methane (SRM) was carried out over alumina supported nano NiO catalyst in silica synthesized using sol-gel method. The crystallite size of NiO in NiO-SiO2 catalysts was found to vary with the calcination temperature and the extent of Ni loading in the catalyst. The NiO crystallite size was found to be 9-15 nm in the Ni loading range of 5-15% and calcinations temperature range of 350-500 degrees C studied. Catalyst containing 10% Ni was found to be the best one for steam reforming reaction in terms of methane conversion. The catalyst was found to be very active and stable in the temperature range of 500-700 degrees C. The most favorable reaction condition was established at a temperature of 700 degrees C, steam to methane molar ratio of 3.5 and a space-time of 11.31 kg cat h/kmol of inlet methane. At this optimum condition, the conversion of methane was 95.7% and the yield of hydrogen was about 3.8 moles of hydrogen per mole of methane reacted. (C) 2012 Elsevier B. V. All rights reserved.