In this work, the preparation of Ni-Al and Zn-Cr layered double hydroxides (LDHs) and their transformations upon calcination are described. The LDHs were prepared from their nitrate salts by pH controlled precipitation. They were characterized before and after calcination by scanning electron microscopy (SEM). X-ray diffractometry (XRD) and BET surface area measurements. The acid-base properties of the dehydrated materials were also investigated by temperature programmed CO, desorption and the double-bond isomerization reaction of I-butene. It was found that upon calcination mixed oxides with large surface areas were formed, which possessed mainly acidic sites of moderate strength.