Mineral composition and content analysis of selected trace elements (Ag, As, Ba, Be, Br, Cd, Ce, Co, Cr, Cs, Cu, Ga, I, La, Li, Mn, Mo, Ni, Pb, Rb, Sb, Se, Sn, Sr, Ti, Tl, U, V, and Zn; 308 rock samples) were studied in the Upper Permian (Zechstein) potash-bearing deposits in Poland. They represented K–Mg chlorides of PZ2 and PZ3 cyclothems from four salt domes and stratiform K–Mg sulphates of PZ1 cyclothem. The dominant mineral components of K–Mg sulphates (polyhalite) are anhydrite and polyhalite. The most common minerals of the K–Mg salts of PZ2 cyclothem are halite, sylvite, kieserite, and anhydrite, and the most common of PZ3 cyclothem are halite, carnallite, kieserite, and anhydrite. Most analysed trace elements in the Zechstein potash-bearing deposits show a low content (up to 26 mg/kg) that eliminates them as potential profitable source rocks of such required elements as Ce, Cs, La, Li, or Rb. Common elements, such as Br, Fe, and Sr, are more easily exploited from natural brines, sulphate, and ore deposits.