Magnetic iron oxide nanoparticles (MNPs) have been synthesized and fully characterized by using different spectroscopic techniques such as transmission electronmicroscopy (TEM),X-ray diffraction (XRD) and infrared spectra (FT-IR). The synthesized particles used as a friendly nanoadsorbent for adsorption trivalent rare earth ions RE3+ (La3+ and Gd3+) from aqueous solution. The adsorption of La3+ and Gd3+ as a function of contact time, initial solution pH and temperature was investigated. Moreover, kinetics and thermodynamics were studied to understand the adsorption mechanism of La3+ and Gd3+ into the synthesized MNPs. The obtained thermodynamics functions ïH, ïS and ïG reveal that sorption is thermodynamically driven. In addition, the adsorbed La3+ and Gd3+ can be readily desorbed 99% from theMNPs surface by using 0.5 Mnitric acid.