The concentration of zinc, copper, selenium, albumin, and ceruloplasmin in blood plasma and the activity of superoxide dismutase and glutathione peroxidase in erythrocytes were determined in a set of patients with idiopathic scoliosis (n=51). A significant decrease of selenium concentration (0.50 +/- 0.16 micromol/L) was found when compared with a control group (0.69 +/- 0.07 micromol/L) (p<0.01). The same levels of significance were found out for selenium levels corrected for albumin content. In a group of patients with a curvature over 45 degrees indicated for a surgical correction, the average plasma concentrations of selenium were significantly lower (p < 0.05) in comparison with a group of patients with a curvature below 45 degrees treated conservatively. The GSH-Px activity in erythrocytes was the same in both sets. In comparison with the controls, no significant differences were revealed in all of the other parameters. The detection of the decreased blood plasma concentration of selenium has suggested possible disturbance of well-proportioned distribution and of general optimal availability of selenium in the organism of patients with idiopathic scoliosis with likely effects on the process of synthesis and maturation of collagen affecting the axial skeleton stability.