The thermal decomposition in air of 2,6-dichlorobenzoates of rare earth elements (Y, La-Lu, except Pm) was studied. During heating, the hydrated complexes Ln(C7H3Cl2O2)(3) .nH2O (n = 1, 2, 4, 6) decompose in three steps, with the exception of cerium, which decomposes in two steps. When heated, the hydrated complexes lose all their molecules of water of crystallization and then decompose to the oxides with intermediate formation of LnOCl, except the Ce(III) complex which decomposes directly to CeO2.