The title compound, C8H8N3S+.Cl-.2H(2)O, has been synthesized and characterized both spectroscopically and structurally. The structure consists of 1,3-benzothiazole-6-carboxamidinium cations, chloride anions and water molecules, all interconnected by hydrogen bonds into a three-dimensional network. The 1,3-benzothiazole moiety is inclined to the 6-amidine group by 36.71 (9) degrees.