Abstract: A study on magnesium (Mg) adsorption was carried out in three Malaysian rice soils (Guar, Hutan and Kangar series) using six levels of Mg (0, 46.3, 54.0, 61.7, 69.4 and 77.2 mmol kg‾1). The Langmuir, Freundlich and Temkin adsorption equations were fitted to the Mg adsorption data. Magnesium adsorption by the Guar and Kangar soils but not the Hutan soil was described well by the Langmuir equation. Magnesium adsorption by the Kangar soil was well described also by the Freundlich and Temkin equations whereas the adsorption data in other two soils did not fit these equations. A significant correlation was found between Mg adsorption and soil pH, while there was no correlation between Mg adsorption and either organic matter content or cation exchange capacity. These results indicated that Mg adsorption is mainly dependent on soil pH. In soils with a higher adsorption capacity, more Mg fertilizer may be needed to get an immediate crop response.