Abstract Mars observations were made during the 1969 opposition using the 22 m radio telescope of the Crimean Astrophysical Observatory of the Academy of Sciences of the USSR. The brightness temperature of Mars was determined by comparing the intensity of its radio emission with that of Jupiter, the brightness temperature of which was taken to be 140 ± 20°K at λ = 2.3 mm and 144 ± 23°K at λ = 8.15 mm. With this assumption, the Mars radio temperatures were found to be 240 ± 30°K at 2.3 mm and 210 ± 30°K at 8.15 mm. These data, as well as the results of some other Mars observations, show that the ratio of the penetration depth of the electrical and thermal waves into the soil of the planet is 1.8 ± 1.2 times the wavelength in cm. The specific loss tangent of the Martian materials is (9.4 ± 6.2) × 10 −3 and is consistent with the value 8 × 10 −3 obtained for the Moon.