The aim of the research was to determine the concentration of selected macroelements in soil and in root crops (potatoes and fodder beets) at a variable soil reaction. The changes in pH values in the studied soils influenced the content of these elements in soluble forms determined in 0.1 mol HCl·dm-3. A statistical analysis showed a positive relationship between the soil pH value and the calcium and magnesium contents in a form close to the total form, as well as the content of soluble forms of phosphorus, calcium, and magnesium. The content of the studied macroelements, i.e. phosphorus, calcium, magnesium in the cultivated fodder beets and potatoes depended on abundance and form in which the studied elements occurred in soil, and also on specie and analyzed part of the plant. Along with the increase in pH values of the an increase in the phosphorus content and reduction of the magnesium content in the roots and above-ground parts of the beets were found. The calcium content in the roots increased along with an increase in pH of the soils, whereas direction of changes in the content of this element in the petioles and laminae of the beets was not unambiguous. A slight decrease in the content of the studied elements in the potato tubers (along with the increase in pH of the soils) was found.