Whey, a valuable byproduct of dairy processing, contains essential proteins like β-lactoglobulin (βLG) and α-lactalbumin (αLA), making it a focus of research for its nutritional benefits. Various techniques, including chromatography and membrane filtration, are employed for protein extraction, often requiring multiple purification steps. One approach that has gained prominence for the purification and concentration of proteins, including those present in whey, is the use of polyethylene glycol (PEG) in aqueous two-phase systems. Our study simplifies this process by using PEG alone for whey protein purification. This approach yielded impressive results, achieving 92 % purity for βLG and 90 % for αLA. These findings underscore the effectiveness of PEG-based purification in isolating whey proteins with high purity.