The hydrogen evolution reaction in molten carbonate salts is an important process in the development of the molten carbonate electrolysis cell (MCEC). In the present study the kinetics of hydrogen production in the Ni porous electrode in a MCEC is investigated. The general procedure is to determine the reaction orders of hydrogen, carbon dioxide and water. For this purpose steady-state polarization data were recorded under different gas compositions and temperatures. The exchange current densities were calculated from the slopes of the polarization curves at low overpotential. On the basis of that, the partial pressure dependencies of hydrogen, carbon dioxide and water could be determined in the electrolysis operation.