The adsorption behavior of cesium on pure minerals is reviewed. Although this field has been investigated intensively, the data are extremely variable in scope and interpretation with detailed information being available for only a few minerals. In current investigations in this field, the emphasis is on the nature of the adsorption sites and identification of these sites using spectroscopic techniques. In the first section of this review, the general mechanism of cesium adsorption is discussed and this is followed by consideration of the effect of parameters such as cesium concentration, the properties of the mineral and the characteristics of the solution phase, on cesium adsorption. Finally, interaction of cesium with some different minerals is described in some detail.