In the mol-ecule of the title compound, C(13)H(10)ClN(3)OS, the dihedral angles between the plane through the thio-urea group and the pyridine and benzene rings are 53.08 (3) and 87.12 (3)°, respectively. The mol-ecules are linked by inter-molecular N-H⋯N hydrogen-bonding inter-actions to form a supra-molecular chain structure along the a axis. An intra-mol-ecular N-H⋯O hydrogen bond is also present.