The title complex Mn(H2O)(2)(HNiC)(2) (C12H12MnN2O8, M-r= 367.18) crystallizes in monoclinic, space group P2(1)/c with a = 7.5735(8), b = 12.5295(13), c = 7.6466(8) angstrom. beta = 101.2790(10)degrees, Z = 2, V = 711.59(13) angstrom(3), D-c = 1.714 g/cm(3). mu(MoKa) = 0.974 mm(-1), F(000) = 374, R-1 (1255 observed reflections (I > 2 sigma(I)) = 0.0250) and wR(2) = 0.0662 (all data). In this paper, we report the complexation of Mn(II) by the bidentate ligand 2-hydroxynicotinic acid (HNic). In the crystal the Mn(II) ion exhibits a deformed octahedron structure. The title complex Mn(H2O)(2)(HNic)(2) has a three-dimensional (31)) network structure extended by hydrogen bonds, which are formed by two typical eight-membered hydrogen-bonded rings.