A summary of the work on the alkali soils in Hungary, comprising the investigations reported chiefly in Hungarian for the last 20 years. Alkali soils may originate under arid and semiarid conditions, where in the past there has been a temporary abundance of humid periods intersected by dry ones. In the case of Hungarian alkali lands this was effected by large inundations resulting partly in swampy and peaty lands and partly in alkali soils. Another combination of favorable conditions for alkali soils was the collection of seepage water in the large sandy territory between the Danube and the Tisza Rivers, the bottom of these lowlands being impervious clay or calcareous hardpan. In both cases there was an opportunity for Na salts to accumulate on the surface, and the concentrated Na salt solutions reacted with the zeolite-humate complex in the soil to replace in some degree the Ca, Mg, and K ions. The degree of this replacement was different according to local circumstances, depending not only on the concentration of the solution lodging in the soil, but also on the ratio of the cations in the solution and the original composition of the solid phase of the soil, which regulates the equilibrium of the whole reaction according to the law of mass action.