The title Co(II) complex, [Co(C(9)H(9)O(2))(2)(C(10)H(14)N(2)O)(2)(H(2)O)(2)], contains two 4-ethyl-benzoate (PEB), two monodentate diethyl-nicotinamide (DENA) ligands and two water mol-ecules. The four O atoms in the equatorial plane around the Co(II) ion form a slightly distorted square-planar arrangement, while the slightly distorted octa-hedral coordination is completed by the two N atoms of the DENA ligands in the axial positions. Intra-molecular O-H⋯O hydrogen bonds link the water mol-ecules to the carboxyl-ate groups. The dihedral angles between the carboxyl-ate groups and the adjacent benzene rings are 4.52 (18) and 4.56 (18)°, while the pyridine rings and the benzene rings are oriented at dihedral angles of 7.76 (10) and 5.67 (13)°. In the crystal, inter-molecular O-H⋯O hydrogen bonds link the mol-ecules into chains propagating along [010]. C-H⋯O inter-actions and a π-π contact between the pyridine rings [centroid-centroid distance = 3.476 (2) Å] are also observed.