Novel bio-/organic-inorganic hybrid compounds of deoxyribonucleic acid (DNA) and methotrexate (MTX)-layered double hydroxide are prepared by ion-exchange type intercalation reaction, The layered inorganic support, Mg2Al(NO3)-LDH, is at first obtained by coprecipitation in an aqueous solution. and then the interlayer NO3- anions are replaced by guest molecules such as methotrexate (an anticancer drug) and deoxyribonucleic acid (about 500 similar to 1000 base pairs), lending to form new bio-/organic-nanohybrids. Upon intercalating guest molecules into hydroxide layers, the basal spacing of LDH increases from 8.5 Angstrom (NO3-) to 20.8 Angstrom (MTX) and 23.9 Angstrom (DNA), respectively. According to the X-ray diffraction and infrared spectroscopic analyses, it is found that the target molecules are safely preserved by hydroxide layers maintaining their chemical and structural properties.