Thermal conductivity measurements of 6HSiC crystals were done in the 300–500 K range by means of radiation thermometry. Bothp‐ andn‐type crystals with carrier concentrations in the 8×1015to 1020cm−3range were used. For the purest samples it was found that the thermal conductivity normal to thecaxis is proportional toT−1.49, the room‐temperature value being 3.87 W/cm deg. It was also found that the thermal conductivity parallel to thecaxis is about 30% lower than that normal to thecaxis. Electrical data in the 100–1000 K range are also presented.