This study examined the concentration of total mercury (THg) and selenium (Se), as well as the molar ratio of Se:THg in hair samples of terrestrial animals. THg and Se concentrations were measured from the hair of raccoons (Procyon lotor) and European wildcats (Felis s. silvestris) from Germany and Luxembourg. Median THg concentrations in hair from raccoons and wildcats were 0.369 and 0.273 mg kg.sup.-1 dry weight (dw), respectively. Se concentrations were higher in the hair of raccoons than of wildcats (0.851 and 0.641 mg kg.sup.-1 dw, respectively). Total mercury concentration in hair of raccoons from Luxembourg was almost 5x higher that found in hair of raccoons from Germany; however, Se concentration was similar. Thus, molar ratio of Se:THg was ~4x higher in the hair of raccoons from Germany than those from Luxembourg. Significant negative correlation was found between THg concentration and Se:THg molar ratio in both wildcats and raccoons.