The title compound, C6H7N3S, crystallizes with two essentially planar molecules in the asymmetric unit (r.m.s. deviation for all non-H atoms = 0.055 and 0.006 Å), which are held together by two N—H...S hydrogen bonds. The two molecules are almost identical (r.m.s. deviation for all non-H atoms = 0.066 Å). An intramolecular N—H...N hydrogen bond stabilizes the synperiplanar conformations between the pyridine N atom and the thiocarbonyl C atom, as well as between the pivot C atom of the pyridine ring and the NH2 group [torsion angles: N—C—N—C = 7.3 (3) and −1.0 (3)°, C—N—C—N = −4.1 (3) and −0.4 (3)°].