The title trimethyl-tin(IV) carboxyl-ate, [Sn(CH(3))(3)(C(11)H(11)O(2))](n), is a carboxyl-ate-bridged polymer in which the Sn atom exists in a trans-C(3)SnO(2) trigonal bipyramidal coordination. One Sn-O bond is a covalent bond [2.114 (2) Å], whereas the other is a dative bond [2.607 (2) Å]. The polymeric chain propagates along the b axis of the monoclinic unit cell.