The title compound, C5H10N2S5, was unintentionally obtained as the product of an attempted synthesis of a methyl-carbamodithioic acid using methylamine and carbon disulfide. In the molecule, two dithiocarbamate groups are bridged by a -CH2S- unit. The C-S-S-C torsion angle is -90.13 (11)degrees. The crystal structure is stabilized by N-H center dot center dot center dot S interactions between neighbouring molecules. An intramolecular N-H center dot center dot center dot S hydrogen bond also occurs.