The title compound, C8H10N2O2S, was prepared by the reaction of 2-cyano-3,3-bis(methylsulfanyl)acrylate and 2-aminoethanethiol at 350 K. The molecular structure and packing are stabilized by N—H⋯O hydrogen-bond interactions. All the non-H atoms are nearly in the same plane with the maximum deviation being 0.08 Å