A study is reported on the thermal evolution of Mg, V layered double hydroxides with interlayer carbonate anions and different Mg/V molar ratios (from 1 to 4). Decomposition in O 2 occurs at lower temperature than that in N 2 ; the stability of the layered structure decreases as the V content increases. Oxidation of layer V 3 + cations occurs in the same temperature range as dehydroxylation and decarbonation. The nature of the crystalline phases formed upon calcination at high temperatures strongly depends on the Mg/V molar ratio in the initial solid.