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Thermal diffusivity of the upper horizons of leached meadow chernozemic soils varies in depen dence on the soil water content within the following limits: 1.20-4.11 × 10 -7 m 2 /s for the Ap horizon, 1.21-3.85 ×10 -7 m 2 /s for the A1 horizon, and 1.35-3.73 × 10 -7 m 2 /s for the A1B horizon. The relationships between the thermal diffusivity and the soil water content are described by S shape curves with a long gently inclined segment within the range of water contents of <0.20 cm 3 /cm 3 , a distinct rise in thermal diffusivity within the water contents from 0.20 to 0.30-0.35 cm 3 /cm 3 , and a flattened or somewhat declining segment in the area with the high (>0.30-0.35 cm 3 /cm 3 ) water contents. The thermal diffusivity of air dried soil sam ples correlates with the physical clay (<0.01 mm) content. The Pearson correlation coefficient for these two variables equals -0.67 and is statistically significant at the significance level of 0.05. Regression equations allowing one to calculate the thermal diffusivity of the investigated soil horizons on the basis of data on the soil water content have been obtained.