This dataset consists of genotypes of 640 animals for 39921 variants (SNPs). Animals belong to 21 Mediterranean cattle populations. The compressed archive contains two files (in plink format): i) a genotyping data file named "MED_set.ped" (640 rows, 79848 columns) that contains, for each individual, six information columns (breed ID, animal ID and four columns with data coded 0 or U) and the genotypes (alleles 1 and 2) for the 39921 SNPs (ACGT, Illumina TOP format) ; and ii) a map file named "MED_set.map" (39921 rows, 4 columns) that contains for each SNP, the autosome number, the SNP name, a column with data coded 0 and the SNP position on autosome.