Magnetically modified clays are low cost materials with promising properties for using in sorption of pollutants from wastewaters. The influence of extraction agents on released of iron oxides nanoparticles (NPs) from magnetically modified kaolinite was studied in this article. Stability of mentioned new smart material was evaluated by leaching test. Characterization of prepared sample was investigated using X-ray fluorescence spectroscopy, X-ray powder diffraction spectroscopy, IR spectroscopy and SEM. Leachates were prepared according to European technical standard EN 12457-2. Material was interacted with demineralization water and extraction agents treated by solution of H2SO4 on pH 2 and 4 or NaOH solution on pH 9 and 11 by discontinuous rotation container at laboratory temperature for 24 hours. The stability of magnetically modified kaolinite was evaluated on the basis of released Fe, Si, Al and accompanying elements in kaolinite structure. Elements were determined after decomposition of filtrate in HNO3 and H2O2 by atomic emission spectrometer with inductively coupled plasma.