The title compound, C(5)H(6)ClN(3), was synthesized by the reaction of 2,3-dichloro-pyridine and hydrazine hydrate. An intra-molecular N-H⋯Cl hydrogen bond results in the formation of a planar (mean deviation 0.038 Å) five-membered ring. In the crystal, inter-molecular N-H⋯N hydrogen bonds link the mol-ecules into a three-dimensional network.