In the title compound, [Cu(C(5)H(10)NO(2))(C(12)H(8)N(2))(H(2)O)]NO(3)·2H(2)O, the Cu(II) atom displays a distorted square-pyramidal coordination (τ = 0.03) where the water mol-ecule occupies the apical position and the base is defined by the N atom, one of the O atoms from the valinate ligand, and both phenanthroline N atoms. The phenanthroline chelate ring plane is slightly distorted from planarity (r.m.s. deviation = 0.0057 Å), whereas the five-membered ring formed by the valinate ligand presents an envelope conformation with the N atom being the flap atom. The crystal packing is stabilized by O-H⋯O and N-H⋯O hydrogen-bonding inter-actions, creating a three-dimensional network superstructure.