The influence of addition of MgSO₄·7H₂O on biomass yield of Saccharomyces cerevisiae was evaluated in this study. Capacities of binding magnesium ions by S. cerevisiae yeast during cultivation on the YPG-medium (laboratory) and in the industrial scale were analyzed. It was stated that in the industrial conditions the higher amount of magnesium in the respective propagation is required. In the laboratory conditions the yield of yeast cultivated on the experimental media enriched with different amount (0,05, 0,3 and 0,5 g·dm^-3) of magnesium ions was also significantly higher than the yield from YPD – control medium. Growing concentration of magnesium ions in the experimental media caused the increasing of magnesium content in the yeast biomass.