A mono-frequency dielectric model for a tundra organic-rich soil both thawed and frozen has been developed. The model is based on the soil dielectric measurements carried out in the ranges of volumetric moisture from 0.007 to 0.573 cm3/cm3, dry soil density from 0.564 to 0.666 g/cm3, and temperature from 25 to −30 °C (cooling run), at the frequency of 1.4 GHz used by the SMOS instrument. To fit the results of measurements of the soil complex refractive index (CRI) as a function of soil moisture, the refractive mixing model was applied. As a result, the parameters of the refractive mixing model linked to soil solids, as well as the bound, transient, and free soil water components were derived as a function of temperature. The error of the proposed dielectric model was shown to be in the order of the dielectric measurement error itself1.