Recently, deoxyribonucleic acid (DNA) adsorption on solid materials has been reported for applications such as genetic diagnosis of diseases, gene delivery, and biosensors. Mesoporous silica (MPS) is an excellent carrier because of its high surface area and large pore volume. Functionalization of the MPS surface can be controlled by silane coupling reagents, and the MPS particle morphology can be easily changed by the synthetic conditions. In this study, to evaluate the ability of DNA adsorption on MPS, the MPS surface was functionalized using four reagents, 3-aminopropyltriethoxysilane (−NH₂), N-(2-aminoethyl)-3-aminopropyltriethoxysilane (−2ENH₂), N-(6-aminohexyl)aminopropyltrimethoxysilane (−2HNH₂), and (3-trimethoxysilylpropyl)diethylenetriamine (−3NH₂), each having a different number of amino groups and alkyl chain lengths. Moreover, we prepared three types of MPSs with different particle morphologies: sheet-type structure (MPS sheet), spherical MPS (MCM-41s), and nonporous spherical silica. A high adsorption capacity was observed in MPS sheets with −2HNH₂ (sheet-2HNH₂) and −3NH₂ (sheet-3NH₂), as well as MCM-41s with −3NH₂ (41s-3NH₂). The adsorption and desorption rates of DNA on these three MPSs were then examined and the best results were obtained with 41s-3NH₂. These results demonstrate that the amino functionalized MPS materials are useful DNA adsorbents.