The relative susceptibility to classical scrapie is mainly determined by polymorphisms at codons 136, 154 and 171 of the prion protein (PrP) gene (Hunter et al., 1996). Five haplotypes, defined by the combination of variants at these three codons are commonly found in sheep; scrapie eradication programmes in several countries are based on changing their frequencies. In Suffolk sheep, one codon shows variation, with the R allele associated with resistance and the Q allele associated with susceptibility. Genotyping costs may be reduced by utilizing information from relatives to infer the genotypes of other relatives. The objectives of this study were to determine the effectiveness of predicting PrP genotypes using information from relatives and to investigate the association of PrP gene with lamb performance traits in Suffolk sheep.