The Ni atom in the title complex, [Ni(SO(4))(C(15)H(13)N(5))(H(2)O)]·H(2)O, has a distorted trigonal-bipyramidal coordination formed by the tridentate 2,6-bis-(2-pyridylamino)pyridine (tpdaH(2)) ligand, one sulfate and one coordinated water mol-ecule. The tpdaH(2) ligand is three-coordinated, with the N atom of the central pyridine ring in the equatorial position [Ni-N = 1.9961 (14) Å] and the N atoms of the peripheral pyridine rings in the axial positions [Ni-N = 1.9668 (15) and 1.9895 (15) Å]. The remaining equatorial positions are occupied by the O atoms of the sulfate ligand and the water molecule. The H atoms of both NH groups of the tpdaH(2) ligand are involved in hydrogen bonds with the O atoms of the uncoordinated water mol-ecule and the sulfate group which link the complex mol-ecules, forming an infinite three-dimensional network.