A hydrazone ligand (H 2PAPH) derived from pyruvic acid and 4-pyridine carboxylic acid hydrazide and its manganese(II) complex have been synthesized and X-ray diffraction analysis of the complex was carried out. The crystal is monoclinic, space group P2 1/n , with unit-cell dimensions a = 11.252(1), b = 9.828(2), c = 13.708(2) Å, β = 66.03(1)° and V = 1385.2 Å, Z = 4, D c = 2.812 g cm −3, F(000) = 1216, μ(Mo-K α) = 18.506 cm −1. The structure was solved by the heavy-atom technique from 2417 observed, independent reflections recorded at 293 K and refined to a final R = 0.028. The manganese atom has a distorted octahedral coordination with two trans water molecules in axial sites and an NO 3 donor set from hydrazone ligands (H 2PAPH) in the equatorial plane. The complex has a polymeric structure. The crystal structure also contains 2.5 water molecules of crystallization, which are involved in a hydrogen-bonding network in the crystal packing. The complex has been also characterized by elemental analysis and IR spectra.