Human selenium status of various groups of Bashkortostan population was studied. Mean serum selenium levels for healthy adults of Ufa, Salavat, Sterlitamak were 98 +/- 11 mg/l (n = 92), 96 +/- 10 mg/l (n = 35), 103 +/- 11 mg/l (n = 20). Serum selenium concentrations for rural populations were found to be smaller: Tolbasy - 84 +/- 13 mg/l (n = 10), Chishmy - 87 +/- 10 mg/l (n = 11), Ufa suburb - 86 +/- 9 mg/l (n = 10). 7-10 years old children of Ufa demonstrated 83 +/- 11 mg Se/l serum and 11-14 years old group - 95 +/- 11 mg/l. Pregnant women serum selenium happened to decrease by 20-30% at the end of the second part of gestation and reached the values of 55-70 mg/l in small settlements. Thus epidemiological data show the possibility of potential selenium deficiency risk for rural pregnant women and 7-10 years old children in Bashkortostan.