There is considerable interest in the eradication of all transmissible spongiform encephalopathies (TSE’s) in food producing animals, to minimise any possible risk to human health. Scrapie, a TSE and a notifiable disease, is a fatal neuro-degenerative disease of sheep and goats. Susceptibility is strongly linked to the prion protein (PrP) genotype on three codons 136, 154 and 171. The ARR alleles confer the greatest resistance to disease; ARQ and ARH are intermediates, whereas VRQ confers greatest susceptibility. UK and EU eradication policies are presently selecting for resistance to scrapie and farmers are taking advantage of genotyping schemes to position themselves better in the market place should scrapie resistance become a major market requirement. The objectives of the study were to find out PrP genotypic frequencies and thus PrP gene-associated susceptibility to scrapie in a flock of Welsh mountain sheep and to predict changes in scrapie genotypes as a result to selection.