Within the framework of an epidemiological survey focused on the problem of iodine deficiency in the Czech Republic the authors examined sonographically in the course of 10 years (1990 - 2000) in 10 selected districts of the Czech Republic 2682 children aged 6, 10, 13 and 17 years (1338 girls and 1344 boys). The representative group was obtained by random selection from the register of inhabitants of the Czech Republic. The examinations were made on a Hewlett-Packard Sono 100 apparatus by assessment of the length, depth and width of every lobe and using these data in Brunn’s formula for calculation for each lobe separately. The volume of the thyroid gland was assessed by the sum of volumes of individual lobes. The isthmus was not included in the overal volume. The total thyroid volume was referred to the body surface. Based on recommendations of WHO and ICCIDD for assessment of standards a group of 1127 children (519 girls and 608 boys) were selected where the iodine level in the examined specimen ofmorning urine was above 100

        Key words: volume of thyroid gland, child population, sonography, iodine supply