Objective: The aim of this study was to determine the Th1 and Th2 serum cytokines, in patients with psoriasis and to compare their cytokine levels with those of normal control subjects.Methods: Serum levels of Interferon-gamma (IFN-γ), Interleukin-2 (IL-2), Interleukin-4 (IL-4), and Interleukin-10 (IL-10) were measured by enzyme linked immunosorbent assay in 40 patients with psoriasis and in 40 normal controls.Results: Compared with control subjects, patients with psoriasis had elevated levels of IFN-γ and IL-2 (P<0.001). In addition, a positive correlation was found between the levels of IFN-γ, IL-2 and disease severity.Conclusion: These results imply that Th1 secreting inflammatory cytokines may contribute to the pathogenesis of psoriasis.