T-cell immunoregulatory cytokines influence the persistence of hepatitis C virus (HCV) chronic infection and the extent of liver damage. Th1 cytokines positively correlate with hepatic inflammation in chronic hepatitis B virus (HBV) infection. The pro-inflammatory, cytokines IL-6 and IL-18, are involved in viral clearance and in metabolic and viral hepatic diseases, respectively. The aim of this study was to evaluate the profile of Th1/Th2 cytokines in HCV and HBV hepatitis. HBV-infected patients showed higher plasma IFN-gamma levels than the HCV+ patients or the control group (p <0.0001). Plasma TNF-alpha and IL-2 were higher in HBV+ in comparison to HCV+ patients (p <0.001) or the control group (p <0.005). Plasma IL-6 and IL-18 were higher in both groups of patients compared to the control group (p <0.04). In HCV+ and HBV+ groups, IL-6 was positively correlated with the duration of the illness (p <0.01 and <0.001, respectively) and viral load (p <0.001 and <0.001, respectively), while IL-18 was positively correlated with serum ALT activity (p <0.01 and <0.001, respectively) and serum AST activity (p <0.01 and <0.001, respectively). We found that in HCV+ and HBV+ patients there are higher levels of Th1 cytokines, particularly in the course of chronic hepatitis B, and that IL-18 and IL-6 levels may have important roles as markers of both inflammation and hepatic injury, particularly in the course of hepatitis C.