A phase transition was found to occur at approximately 153 K in the title compound, (C8H20N)2[PdCl6]. The structures of the two phases are reported at 292 and 130 K. The low-temperature phase is twinned. The phase transition is accompanied by a minor displacement of the ions. There are C-H...Cl interactions as short as approximately 2.80 A, indicating the existence of hydrogen bonds, and this was confirmed by vibrational spectroscopy. The [Pd2Cl6]2- anion occupies sites of mmm and 2/m symmetry in the room-temperature and low-temperature phases, respectively.