The process of plasma-assisted conversion of propane and its mixture with methane in the presence of water in a dielectric-barrier discharge (DBD) has been studied. The products of the processing of feed mixtures are hydrogen, C-1-C-4 gaseous hydrocarbons, and C-5-C-12 liquid alkanes of isomeric structure. The observed findings are explained in terms of electron-molecule reactions involving propane and methane molecules at the stage of discharge initiation under DBD plasma conditions.