Catalytic decomposition of methane into COx-free hydrogen and carbon nanofibers has recently attracted much attention. The development of high-performance catalysts is essential for production of COx-free hydrogen from methane. In this review we summarize the catalytic systems used for methane decomposition and compare catalysts with different active components and supports. According to the literature and our recent research results, Ni is the most active metal for methane decomposition and its catalytic performance can be enhanced by doping with metals such as Pd and Cu, especially for high reaction temperatures. The nature and origin of the surface are the main factors that influence the performance of carbon catalysts.