Oxyreforming is the conversion of methane with oxygen into a mixture of carbon monoxide and hydrogen. It is demonstrated that nickel based catalysts exhibit high potential for this reaction. In order to obtain high yields of CO/H-2, high reaction temperatures are needed, of the order of 973 to 1173 K. Small amounts of carbon dioxide and water are formed. Detailed thermodynamic calculations of different reaction models have been carried out. It has been found that the experimental oxyreforming can be described by the combustion of methane into carbon oxides and water, in combination with steam reforming and water-gas-shift reactions.