The title Co-II complex, [Co(C9H9O2)(2)(C10H14N2O)(2)(H2O)(2)], contains two 4-ethylbenzoate (PEB), two monodentate diethylnicotinamide (DENA) ligands and two water molecules. The four O atoms in the equatorial plane around the Co-II ion form a slightly distorted square-planar arrangement, while the slightly distorted octahedral coordination is completed by the two N atoms of the DENA ligands in the axial positions. Intramolecular O-H center dot center dot center dot O hydrogen bonds link the water molecules to the carboxylate groups. The dihedral angles between the carboxylate groups and the adjacent benzene rings are 4.52 (18) and 4.56 (18)degrees, while the pyridine rings and the benzene rings are oriented at dihedral angles of 7.76 (10) and 5.67 (13)degrees. In the crystal, intermolecular O-H center dot center dot center dot O hydrogen bonds link the molecules into chains propagating along . C-H center dot center dot center dot O interactions and a pi-pi contact between the pyridine rings [centroid-centroid distance = 3.476 (2) angstrom] are also observed.