In this study, we investigated the gamma-ray shielding ability and iodide selectivity of layered double hydroxide (LDH) with chloride anions. LDH consisting of Ni and Al (NiAl(x)LDH, x = Al contents) with carbonate and iodide anions theoretically shielded about 50 and 90% of gamma-rays from the I-129 nuclide, respectively. This selectivity could be explained by comparing the cross-section area of iodide with that of the anion-exchange site of NiAl(x)LDH.