The title compounds [R 2NH 2][C 2O 4SnMe 3](Ri-Bu, Cy), in which tin atoms adopt a distorted trigonal bipyramidal configuration, have been prepared and submitted to an X-ray diffraction study. These compounds have been obtained from the reaction of (Cy 2NH 2) 2C 2O 4· H 2O or (i-Bu 2NH 2) 2C 2O 4 with SnMe 3Cl. In both [R 2NH 2][C 2O 4SnMe 3] compounds, the trans complex has an almost regular trigonal bipyramidal geometry around the tin atom. The SnMe 3 residues are connected as a chain with bridging oxalate anions in a trans-SnC 3O 2 framework, the oxygen atoms being in axial positions. The cations connect linear adjacent chains through NH..O hydrogen bonds giving layered structures.