Fe3O4 nanoparticles as well as 1-hexyl-3-methylimidazolium bromidecoated Fe3O4 nanoparticles were prepared and used for adsorption of DNA. The mean size and the surface morphology of both nanoparticles were characterized by TEM, DLS, XRD, FTIR and TGA techniques. The correlation coefficient of the Langmuir model suggests a better fit for the experimental equilibrium adsorption data.