Abstract INTRODUCTION: The aim of this study was to measure serum levels of interferon-gamma (IFN-γ) and interleukin-4 (IL-4), the two major cytokines secreted by Th-1 and Th-2 cells, in islet cell autoantibody (ICA)-positive, newly-diagnosed type I diabetic patients. methods: The study was conducted on 30 newly diagnosed, ICA-positive type I diabetics and 30 age- and sex-matched healthy controls. Cytokine levels in serum were quantified by indirect sandwich ELISA in pg/ml. results: We observed no significant difference in concentration of IL-4 in ICA-positive diabetics (median=126.535) compared with healthy controls (median=136.440) (P>0.05). IFN-γ levels were significantly higher in patients (median=11.305) compared with healthy controls (median=8.200) (P<0.05). CONCLUSIONS: Increased levels of IFN-γ in patients may be suggestive of its destructive role in the pathophysiology of type I autoimmune diabetes. Keywords: Type I diabetes mellitus, interleukin-4 (IL-4), interferon-gamma (IFN-γ), islet cell autoantibody (ICA), T-helper 1 (Th-1) response, T-helper 2 (Th-2