In the title dinuclear complex, [Ni(2)(C(8)H(7)O(2))(4)(C(12)H(8)N(2))(2)(H(2)O)], each Ni(II) atom is six-coordinated by three carboxylate O atoms from three 4-methyl-benzoate ligands, two N atoms from two 1,10-phenanthroline ligands, and one μ(2)-bridging aqua ligand. The dimeric complex is located on a crystallographic twofold axis and each Ni atom displays a distorted octa-hedral coordination geometry. The crystal structure is stabilized via intra-molecular hydrogen bonding of the bridging water mol-ecule and the uncoordinated carboxyl-ate O atoms, and by C-H⋯O and π-π stacking inter-actions [centroid-centroid distances between neighbouring phenanthroline ring systems and between the benzene ring of a 4-methyl-benzoate unit and a phenanthroline ring system are 3.662 (2) and 3.611 (3) Å, respectively].