The total dissociation cross section for methane is reported for electron energies between 10 and 500 eV. A maximum cross section of 4 × 10 -16 cm2 occurs at 85 eV. Dissociation into ionic and neutral fragments have about equal probability for energies between 50 and 500 eV. At lower energies most of the fragments are uncharged, ground state, or long lived excited state molecules. The experimental technique is discussed in detail and criteria established for determining gases for which similar methods can be applied. Copyright © 1975 American Institute of Physics.