Geochemical background and threshold values need to be established to identify areas with unusually high concentrations of elements. High concentrations are caused by natural or anthropogenic processes. The <2 mm fraction of 817 collected topsoil (0-10 cm) samples at a 5 × 5 km grid on the territory of Slovenia was analysed. Results are used here to establish the geochemical background variation and threshold values, derived statistically from the data set, in order to identify unusually high element concentrations for these elements in the soil samples. Geochemical threshold values were determined following different methods of calculation for (1) whole of Slovenia and (2) for 8 spatial units determined on the base of geological structure, lithology, relief, climate and vegetation. Medians and geochemical thresholds for whole of Slovenia were compared with data for Europe and for southern Europe separately, since large differences in the spatial distribution of many elements are observed between northern and southern Europe. Potentially toxic elements (PTEs), namely As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, and Zn, are of particular interest. Medians of these PTE elements are all higher in Slovenia than in southern Europe. Medians of Pb and Mo are 1.5 times higher and medians of Hg and Cd are even more than 2 times higher in Slovenia. Geochemical thresholds for As, Cr, Co, Ni, Sb and Zn are of similar values in both Slovenia and southern Europe and some lower for Cu and Ni. Up to 1.5 times higher are tresholds in Slovenia for Mo and Pb and more than 2.5 times higher for Cd and Hg. These values were then compared to existing Slovenian soil guideline values for these elements. Izvleček Kemični elementi so v okolju, torej tudi v tleh, naravno prisotni. Povišane vsebnosti le-teh so posledica naravnih danosti ali pa jih povzročijo človekove dejavnosti. Območja povišanih koncentracij elementov so opredeljena kot območja, na katerih vsebnosti elementov presegajo vrednosti geokemičnega praga (zgornjih mej naravne variabilnosti-MNV). Na podlagi kemičnih analiz 817 vzorcev zgornje plasti tal (0-10 cm), odvzetih v mreži 5 × 5 km na območju celotne Slovenije, smo izračunali mediane (geokemično ozadje) in zgornje meje naravne variabilnosti (MNV) po več metodah za celotno Slovenijo in za 8 manjših prostorskih enot, ki smo jih določili glede na geološko zgradbo, kamninsko sestavo, relief, podnebje in rastlinstvo. Znotraj posameznih manjših prostorskih enot se izračunane MNV po različnih metodah močno razlikujejo zaradi heterogenosti enot in majhnega števila vzorcev. Mediane in zgornje meje naravne variabilnosti za celotno Slovenijo smo primerjali s podatki za celotno Evropo in še posebej južno Evropo, ker se prostorske porazdelitve elementov med južno in severno Evropo močno razlikujejo. Zanimive so vsebnosti potencialno strupenih elementov (As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Zn) in primerjava z mejnimi, opozorilnimi in kritičnimi vrednostmi za tla po slovenski zakonodaji. Mediane teh elementov so v Sloveniji višje kot v ce...