Genome-wide SNP panels provide an affordable tool to assess within-breed genetic diversity and between breed relationships, also among closely related populations. A set of 496 animals, representative of 20 local and cosmopolite sheep breeds from different geographic and agro-ecological areas of Italy were genotyped with the Illumina Ovine SNP50 BeadChip. On average, 97% of the loci were polymorphic within breed, with slight differences among breeds. SNP with MAF