The food industry faces the problem of soil contamination and consequently the deterioration of the quality of plant products. Here, we present a study on evaluation of the effect of fertilization with sewage sludge (SL) with varying, rates of biochar (BC 2.5, 5 and 10% of DW) on yield quality and the accumulation of heavy metals in wheat grains. The greatest grain yield with the highest content of protein and gluten as well as the highest total content of phenols and flavonoids, was obtained when SL+5%BC fertilization was applied. The addition of 5%BC and 10%BC to SL resulted in the greatest increase in the antioxidant capacity of grain. Among phenolic acids, syringic acid was found in the largest amount in grain in the SL+2.5%BC treatment. A significant decrease in Pb accumulation in wheat grain after application of SL+5%BC and a successive decrease in Al content with increasing BC addition were observed. To increase the quality of wheat grains and to reduce the bioaccumulation of harmful elements after the application of biochar to the soil is important in the context of food safety and health of humans especially in food production on acidic and/or contaminated soils.