This paper presents a study of -lactoalbumin and -lactoglobulin proteins partition from goat milk whey in-nature, utilizing aqueous biphasic systems comprised of polymers (polyethylene glycol, polypropylene glycol, polyvinylpyrrolidone), potassium phosphate, and water. The systems were evaluated at 25 degrees C and pH 7.0. The influence of the polymer type, of the polymer molecular weight, and the polymer mass percentage on the partition coefficient of these proteins was assessed. Among the analyzed polymers, the polyethylene glycol (1500) was more indicated. The results showed that the separation technique by aqueous biphasic systems are applicable indicating high efficiency in the whey proteins separation process.