Genetic variability of the gene ß-lactoglobulin (BLG) was evaluated by PCR-RFLP with the objective to determine the allelic component of this gene in 267 Creole cattle of rural communities of Ayacucho, Puno and Ancash. In this paper allelic frequencies in Creole cattle of the rural communities of these regions are reported; all populations were in equilibrium (p<0.05). The genotypic frequency of BLGAA was low respect the BLGAB and BLGBB genotypic frequencies. Our results are discussed to associate them to kappa caseins (CASK) genotypes, milk production and cheese yielding of Creole cattle. This information will be useful in future breeding programs, as an alternative to a sustainable economic development to improve life quality of the rural communities of these regions of Peru. It is important to indicate the relevance of the in situ conservation of this specie locally adapted that survives in low-input production systems.