The aim of this study was to investigate the capacity of different yeast strains to grow on acid whey and assimilate different carbon sources. Twenty different yeasts (with GRAS status) were tested, sourced from the LOCK105 Culture Collection (Poland) and the National Collection of Yeast Cultures (Great Britain). The acid whey, from cows was characterized in terms of it main chemical components (carbohydrates, organic acids, aminoacids, FAN, total nitrogen) using HPLC techniques and chemical methods. The best producer of biomass (of conventional yeast strains) was S. cerevisiae Ja64 (biomass yield 1.16 g of dry mass/l), while among non-conventional yeasts the highest increase of biomass showed the strain D. hansenii, reaching the biomass yield of 1.12 g of dry mass/l.