From an acrylonitrile-dimerization liquid product prepared by contacting acrylonitrile with a specific catalyst composed of a metal halide and a trialkylamine, 2-methyleneglutaronitrile is efficiently recovered by a process which comprises contacting the reaction liquid product under stirring with benzene, toluene or xylene as well as with water in specific ratios, and then separating the resulting aromatic hydrocarbon layer from the mixture to recover 2-methyleneglutaronitrile.