In the title compound, [Sm(C9I3O6)(C3H7NO)3] n , the Sm(III) atom is coordinated by nine O atoms, viz. six carboxyl-ate O atoms from three 2,4,6-triiodobenzene-1,3,5-tricarboxyl-ate (I3BTC) ligands and three O atoms from three N,N-dimethyl-formamide (DMF) mol-ecules. Each I3BTC ligand bridges three Sm(III) atoms, generating a three-dimensional metal-organic framework structure. The asymmetric unit contains one Sm(III) ion and one I3BTC anion, both situated on a threefold axis, and one DMF mol-ecule in a general position.