In seven regions of the Czech Republic the magnesiuria and calciuria were determined photometrically using the apparatus Merck Vitalab Eclipse, the selenuria fluorimetrically and the ioduria photometrically after alkaline mineralization in the morning sample of urine (after night fasting) in subjects aged 6-65 years (3,587 probands) selected at random. The lowest magnesiuria was found in children in Klatovy district (5.36 nmol/l +/- 0.11) and the highest magnesiuria was estimated in children from the Ustí nad Labem district (6.59 mmol/l +/- 0.16). In adults the lowest magnesiuria was in Vsetín region (3.78 mmol/l +/- 0.08). Selenuria was lowest in Jindrichüv Hradec (7.60 micrograms/l +/- 0.30) and highest in the Vsetín district (15.07 micrograms/l +/- 0.50). Adults had the lowest selenuria in the region Jindrichüv Hradec (7.67 micrograms/l +/- 0.30) and the highest in Ustí nad Orlicí (11.68 micrograms/l +/- 0.34). The lowest ioduria was estimated in children from Ustí nad Labem (94.30 micrograms/l +/- 2.06) and the highest in the Vsetín region (151.60 micrograms/l +/- 7.55). Adults from the district Jindrichüv Hradec had ioduria merely (77.7 micrograms/l +/- 2.18) and the highest ioduria was found in probands from the Znojmo region (123.30 micrograms/l +/- 4.47). As far as the dependence on age is concerned, the magnesiuria significantly decreases both in children and in adults with the increasing age. Selenuria decreases in adults significantly with growing age. Sex-related differences were estimated in children aged 6 years where girls had significantly lower selenuria than boys and girls aged 13 years had lower ioduria, magnesiuria and selenuria than boys. Women aged 18-35 years had significantly lower ioduria, calciuria and magnesiuria in comparison with men of the same age. Women have a significantly lower ioduria in comparison with men at the age 56-65 years.