The aim of the experiment was to determine the effect of cadmium (10, 20, 30 and 40 mg Cd · kg^-1 soil) on the potassium uptake by oats, maize, yellow lupine and radish. The effect of organic matter on cadmium immobilization was investigated in several treatments of the experiment using non-supplemented soil and soil supplemented with compost soil, brown coal, lime or bentonite. The correlations between the potassium content and the cadmium contamination of the soil, plant yield and the content of macro- and microelements in the plants were determined. The species and organ of the plants determined the uptake of potassium and influenced the effect of cadmium on the uptake of potassium by plants. Artificial soil contamination by cadmium reduced the content of potassium in oat grains and in the above-ground parts and roots of yellow lupine and radish. A reverse effect - an increase in the concentration of potassium, was found for oat straw and roots and maize roots. The application of compost soil, brown coal, lime and bentonite reduced the potassium concentration in the particular organs of the experimental crops. The concentration of potassium was positively correlated with plant yield and the content of macroelements and some microelements in them.