Abstract. The study of the thermal properties of soils. and their determination, is discussed on the basis of the author's statistical-physical model of the thermal conductivity of soils and of de Vries formula concerning the heat capacity of soil. The theory presented in the paper allows for the determination of the basic thermal characteristics of the soil with relation to the moisture, density, tempera­ture and granulometric composition of the soil and to the water potential in the soil. The error of the estimation does not exceed ±10 % of the measured values.