Kaolin, an inexpensive clay mineral, available in abundance in our country has been employed as an adsorbent for the removal of Mg2+ from water at pH 7.0 within the temperature range (303-328 K). The linearity of the plots indicated langmuir type isotherms. The reaction was exothermic. At 303 K the H-rel(+)/Mg2+ ads ratio n was fractional. At 318 K at a time only one H+ was released per metal ion adsorption and at 328 K two H+ were released to the aqueous phase. Strong chemical bondings took place between oxygen atom of the surface and Mg2+ resulting in a surface complex species. In spite of the difference in structure between TiO2 and kaolin, they show a similarity in their interaction with magnesium. Temperature had a significant effect on H-rel(+), and the stability constants also increased with increasing temperature.