Alkali metal salts of terephthalic acid are common reagents in the preparation of metal-ligand coordination complexes containing terephthalate anions. In the title compound, sodium hydrogen terephthalate, [Na(C(8)H(5)O(4))](n), the cations occupy crystallographic inversion centres, and each bridging anion coordinates to six octahedral cations and vice versa. As seen in the known potassium derivative [Kaduk (2000). Acta Cryst. B56, 474-485; Miyakubo, Takeda & Nakamura (1994). Bull. Chem. Soc. Jpn, 67, 2301-2303], sodium hydrogen terephthalate contains short O-H.O hydrogen bonds between anions [O.O = 2.4734 (17) A]. The structure is centrosymmetric and exhibits disorder of the H-atom position in the hydrogen bond and of the non-bridging ring C atoms in the terephthalate ion.