Abstract: We investigated prion protein gene(PRNP) polymorphisms in three sheep breeds in Inner Mongolia, China. Blood samples were collected from 46 Ujumqin, 34 Sunite and 22 Mongolian sheep. The genetic DNA of PRNP of each sheep was extracted, amplified, and sequenced, and amino acid alignment was determined. Polymorphism was detected at 8 codons, among which M157I, Q220H and R223K have not been previously reported. The frequency of the amino acid residues ARQ/ARQ at codons 136, 154 and 171, which is associated with medium-high susceptibility to scrapie, was 74.5%, and the frequency of scrapie-resistant amino acid residues ARR/ARR was 7.9%. The highly susceptible amino acid residues VRQ/VRQ at these codons were not detected from the tested sheep. Of the 3 sheep breeds, Ujumqin sheep had the highest frequency (15.2%) of scrapie-resistant amino acid sequence, ARR/ARR at codons 136, 154 and 171, accounting for 87.5% sheep that carry these polymorphisms. Our findings are of special importance for both live sheep export and sheep breeding.