Although a detailed explanation of the mechanism of immunotherapy is not known, several immunologic explanation have been proposed. It's said that T cell-cytokine profile changed with allergen immunotherapy. In our study we evaluated IFN-* and IL-10 levels before and after immunotherapy in patients with allergic rhinitis. Twenty patients (mean age; 27.3 +/- 4.84), 8 male, 12 female with allergic rhinitis, mean duration of disease was 5.55 +/- 1.23 years and 13 healthy controls, 5 male, 8 female (mean age: 28.38 +/- 5.61) were enrolled in the study. Immunotherapy was performed for grass pollen allergen extract to patients with allergic rhinitis for 31.5 +/- 4.98 months. Serum IL-10 and IFN-* levels were evaluated with ELISA. Serum IL-10 levels were significantly high before and after immunotherapy compared to controls. There was no difference in IFN-* levels before and after SIT compared to controls. According to this study, in patients with allergic rhinitis after immunotherapy serum IL-10 levels are decreased but IFN-* no change.