In a pot experiment conducted in the years 2010-2012, an assessment was performed of the impact of sowing method and density of spring wheat and Persian clover on their uptake and accumulation of P, K and Mg. The experimental factors were: 1) the method of sowing spring wheat and Persian clover: pure sowing (control) and mixed sowing; 2) the plant density: recommended (according to the rules of proper agricultural practice) and lower (reduced by 20% compared to the recommended density). Tests were conducted during the following growth stages of spring wheat sown on the object with pure sowing and recommended plant density: inflorescence emergence (BBCH 54-56) and ripening (BBCH 87-89). Based on the measurements of dry mass of the aboveground parts (vegetative, heads, grains) and roots, as well as the content of P, K and Mg in them, the uptake of those nutrients by both species was calculated. It was demonstrated that the concentration of P and Mg in spring wheat did not change under the influence of undersown Persian clover. K content in spring wheat growing with the undersown crop was lower than the content in pure sowing. The content of P, K and Mg in clover plants in both methods of sowing was similar to that in the inflorescence emergence stage of wheat. In the ripening stage a reduction of those elements was observed. Uptake of P, K and Mg by spring wheat and the undersown Persian clover was lower than in the case of pure sowing. Density of plants did not diversify the uptake of analysed nutrients by wheat. On the other hand, clover took up more magnesium and less potassium in the object with higher plant density.