The asymmetric unit of the polymeric title compound, [Na2(C20H13O5P)(C2H6O)(H2O)5]n, consists of two NaI ions, one 2′-hydroxy-1,1′-binaphthyl-2-yl phosphate anion, one ethanol ligand and five water molecules of crysallization. Each NaI ion has a distorted octahedral coordination geometry. The phosphate anion coordinates to one NaI ion and the ethanol molecule coordinates to the other. The five water molecules bridge the NaI ions, forming an inorganic chain structure along the b axis. The chains are connected by O—H⋯O hydrogen bonds into an organic–inorganic hybrid layer parallel to (001)