Serum levels of sICAM-1, sVCAM-1 and sP-selectin were determined in patients with Graves' disease before and after 8 weeks and 24 months of methimazole therapy, in levothyroxine suppressed patients with non-toxic nodular goiter, and in a group of healthy controls, to elucidate the relationship to circulating antithyroid antibodies and possible role of soluble adhesion molecules as markers of inflammatory activity. sICAM-1, sVCAM-1, and sP-selectin in patients with untreated hyperthyroidism were markedly elevated compared with controls. After 8 weeks of methimazole treatment, the concentrations of these molecules dropped, but were still significantly higher than in healthy children. In patients with clinical and biochemical remission after 24 months of therapy, sICAM-1 values were on the verge of significance, but still higher than in the control group, whereas serum levels of sVCAM-1 and sP-selectin had normalized. Slightly higher serum sICAM-1 values were observed in patients with non-toxic nodular goiter compared with healthy children.