In the title complex, [Co(C7H4ClO2)(2)(C6H6N2O)(2)(H2O)(2)], the Co II atom is located on an inversion center and is coordinated by two 3-chlorobenzoate (CB) anions, two nicotinamide (NA) ligands and two water molecules. The four O atoms in the equatorial plane form a slightly distorted square-planar arrangement, while the slightly distorted octahedral coordination is completed by the two N atoms of the NA ligands in the axial positions. The dihedral angle between the carboxylate group and the adjacent benzene ring is 9.14 (9)degrees, while the pyridine and benzene rings are oriented at a dihedral angle of 82.18 (8)degrees. In the crystal, N-H. . .O and O-H. . .O hydrogen bonds link the molecules into a two-dimensional network lying parallel to (101). pi-pi stacking between parallel pyridine rings of adjacent molecules [centroid-centroid distance = 3.7765 (8) angstrom] further stabilizes the crystal structure.