The structure of the title compound, [Mg(C(10)H(6)O(6)S(2))(C(3)H(7)NO)(2)](n), consists of MgO(6) octa-hedra ( symmetry) connected to naphthalene-1,5-disulfonate ligands ( symmetry) in the equatoral plane, forming a two-dimensional network propagating parallel to (010). The coordination sphere of the Mg atom is completed by the O atoms of two N,N-dimethyl-formamide (DMF) mol-ecules in the axial positions. The title compound represents the first time the naphthalene-1,5-disulfonate anion is bound directly to a Mg(2+) atom. Disorder over two positions was found in the DMF mol-ecule in a 0.518 (8):0.482 (8) ratio.