Interferon(IFN)γ-induced protein 10 (IP-10) and its receptor, CXC receptor 3, appear to contribute to the pathogenesis of Graves' disease (GD) and Graves' ophthalmopathy (GO). Under the influence of IFN-γ, IP-10 is secreted by thyrocytes (in GD), fibroblasts and preadipocytes (in GO). Determination of high level of IP-10 in peripheral liquids is therefore a marker of a Th1 orientated immune response. Circulating IP-10 is associated with the active phase of GD in both newly diagnosed and relapsing hyperthyroid patients. Methimazole reduces IP-10 secretion by isolated thyrocytes, decreases serum IP-10 levels, and promotes a transition from Th1 to Th2 dominance in patients with GD active phase. In GD patients the decrease of IP-10 after thyroidectomy and radioiodine strongly suggests that this chemokine is mainly produced by the thyroid itself. In GO patients the increased concentrations of IP-10, at least in part, reflect the activity of orbital inflammation. A significant reductions in IP-10 serum concentrations during corticosteroids and or radiotherapy treatments, as compared both to control group and to basal values in GO patients, suggest that this chemokine could serve as a guideline in therapeutic decision-making in patients with GO. Further studies are needed to evaluate whether IP-10 is a novel therapeutic target in GD and GO.