Many studies reported that patients coinfected with HCV and schistosomiasis have a more severe clinical course compared with patients infected with HCV alone. Thus we investigate the cellular immune response in patients coinfected with HCV /S.mansoni versus patients infected with either HCV or S.mansoni alone. Methods: peripheral blood CD4+ T-cell and CD8+ T-cell were isolated from 30 patients (10 patients have chronic HCV monoinfection, 9 patients have S.mansoni monoinfection and 11 patients have HCV /S.mansoni coinfection) as well as 10 healthy control and their CD4+ and CD8+ cytokine profile in response to HCV antigens (C25, C33c, NS5) as well as S.mansoni adult worm antigens were determined. Results: among all HCV antigens used, the specific response of T-cells were significantly decrease in coinfected patients in relation to chronic hepatitis C monoinfected patients and the highest IFN-γ production by T-cells were in response to C25 followed by C33c followed by NS5. Conclusion: concomitant infection of S. mansoni and HCV lead to down regulation of specific cellular immune response against HCV which may be the cause of the severe clinical course in coinfected patients.