The title compound, C(8)H(5)BrN(4)O(2)S, was synthesized by the reaction of 4-bromo-2-nitro-benzoic acid with thio-semi-carbazide. The dihedral angle between the thia-diazole and benzene rings is 40.5 (2)°. In the crystal, the strongest N-H⋯N inter-molecular hydrogen bond, between the amine group and one thia-diazole N atom, forms centrosymmetric dimers. The other amine H atom extends the supra-molecular network, forming an N-H⋯N contact with the other thia-diazole N atom.