The centrosymmetric molecule in the monomeric title cobalt complex, [Co(C10H11O2)(2) (C10H14N2O)(2)(H2O)(2)], contains two water molecules, two 2,4,6-trimethylbenzoate (TMB) ligands and two diethylnicotinamide (DENA) ligands. All ligands coordinate to the Co-II atom in a monodentate fashion. The four O atoms around the Co-II atom form a slightly distorted square-planar arrangement, with the distorted octahedral coordination sphere completed by two pyridine N atoms of the DENA ligands. The dihedral angle between the planar carboxylate group and the adjacent benzene ring is 84.2 (4)degrees, while the benzene and pyridine rings are oriented at a dihedral angle of 38.87 (10)degrees. The water molecules exhibit both intramolecular (to the non-coordinating carboxylate O atom) and intermolecular (to the amide carbonyl O atom) O-H center dot center dot center dot O hydrogen bonds. The latter lead to the formation of layers parallel to (100), enclosing R-4(4) (32) ring motifs. These layers are further linked via weak C-H center dot center dot center dot O hydrogen bonds, resulting in a three-dimensional network. One of the two ethyl groups of the DENA ligand is disordered over two sets of sites with an occupancy ratio of 0.490 (13): 0.510 (13).