The crystal structure of catena-poly[[tri-n-butyltin]-mu-3-(1-naphthylaminocarbonyl)acrylato-kappa(2)O(1):O(3)], [Sn(C(4)H(9))(3)(C(14)H(10)NO(3))](n), is composed of polymeric chains wherein the metal center exhibits a distorted trigonal-bipyramidal geometry, with three n-butyl groups defining the trigonal plane [mean Sn[bond]C 2.133 (7) A] and the axial positions being occupied by the carboxylate O atoms of two different N-(1-naphthyl)maleamate ligands with inequivalent Sn[bond]O distances [2.167 (4) and 2.457 (4) A]. The N-(1-naphthyl)maleamate fragment forms an essentially planar seven-membered ring involving an intramolecular N[bond]H...O hydrogen bond.