Electron mobilities were measured in a number ofn‐type SiC samples selected and prepared in such a way as to ensure that they were single polytype specimens of 6H, 15R, or 4H. In the purest samples from the same growth preparation the ratio of 15Rto 6Hmobilities was found to be about 1.7 with both polytypes having a temperature dependence of mobility nearT−2.4between 300° and 800°K. Room‐temperature mobilities of these specimens were about 300 and 500 cm2V−1sec−1, respectively, for 6Hand 15R. Only two 4Hsamples were measured, but these showed even higher mobilities than 15Rpolytype samples.