In this study we determined the serum selenium concentraction of 218 healthy individuals at different ages, in Ankara, using a spectrofluorimetric method. The mean selenium levels were found to be 45 +/- 10 mug/L in cord blood at birth; 69 +/- 13 mug/L in 2 month - 12 month-old infants; 77 +/- 12 gg/L- in children aged > 12 months - 16 years; and 74 +/- 16 mug/L in adults aged 18 - 48 years. Selenium concentrations showed age dependency, increasing significantly in childhood but decreasing after 40 years of age. No relation to the sex, dietary habits, socioeconomical status or hematological parameters such as hemoglobin concentration and white blood cell count, was observed. The results obtained thus suggest that the status of selenium in Ankara residents is in a range that could be considered as safe and adequate.