With the aim of developing a method for the recovery of tritium from tritium-bearing hydrocarbons, it was shown experimentally that methane can be decomposed directly into hydrogen and carbon in RF plasmas via reactions initiated by electrons. Measurements performed with CH4 and CH3T in a helium RF plasma indicate that the degree of decomposition of CH3T is substantially smaller than that of CH4. This is considered to be caused by a very low concentration of CH3T. It was found that a majority of tritium dissociated from CH3T is retained in the plasma reactor. However, a certain amount of retained tritium could be removed by a discharge-cleaning of oxygen.