The study utilized data from a field experiment carried out at the Experimental Station in Zawady owned by the University of Natural Sciences and Humanities in Siedlce in the years 2005–2007. The experimental factors included two soil tillage systems and seven weed control methods in potato. Iron, copper and zinc in weeds were determined with the AAS method. The trace element content in weed dry matter before row closure of potato depended significantly on soil tillage methods (excluding Cu), weed control methods and weather conditions, and, prior to tuber harvest, on soil tillage and weather conditions during the growing season. The uptake of Fe, Cu, and Zn by weeds from the area of 1 hectare depended on the experimental factors, weed biomass and weed chemical composition.