Montmorillonite (MMT) and rectorite (REC) are clay minerals that consist of hydrated aluminum silicate with Si-O tetrahedrons on the bottom of the layer, Al-O(OH)(2) octahedrons on the top, and various exchangeable ions such as Na+ and Ca2+ in interlayer. However, the driving force for intercalation of double-stranded DNA is not sufficient to open up the gallery of MMT and REC and allows the intercalation to occur. Furthermore, the external surface of MMT and REC is hydrophilic rather than organophilic. In the study, cationic hexadecyl trimethyl ammonium bromide (CTAB) is chosen to modify MMT and REC to make clay minerals more compatible with DNA. CTAB intercalates into the galleries of clay minerals and expands the basal spacing for DNA intercalation. Novel CTAB-clay/DNA hybrids are synthesized for the first time, with their structure investigated by X-ray diffraction and Fourier transform infrared. Gel electrophoresis analysis confirms that the CTAB-modified clay could protect DNA from degradation of DNase I. UV absorption spectroscopy and circular dichroism indicate that the modified clay minerals can provide a capacity for protecting DNA from damage induced by heavy metals. In addition, the intercalated DNA can be recovered readily under alkaline conditions. Therefore, CTAB-clay/DNA hybrids are potential materials for storage of genetic information.