In the title compound, [CoNa2(C7H3NO4)2(H2O)2]n, the CoII atom is coordinated by two pyridine N atoms and four carboxylate O atoms from two doubly deprotonated pyridine-2,6-dicarboxylate ligands in a distorted octahedral geometry. One Na+ cation is coordinated by three carboxylate O atoms and two water molecules and the other is coordinated by five carboxylate O atoms and two water molecules in an irregular geometry. The bis(pyridine-2,6-dicarboxylato)cobalt complex units are connected by Na+ cations and bridging water molecules into a three-dimensional coordination network. O—H⋯O hydrogen bonds are formed between the water molecules and the carboxylate O atoms.