Hepatitis C virus infection and schistosomiasis are common in Egypt. Coinfection is not uncommon. Little and quite controversial data are known about biochemical profile in these patients. This study was designed to study IL-2 production as a marker of lymphocyte activity in patients suffering from schistosomiasis with or without hepatitis C virus infection. This work enrolled 513 patients (239 females and 274 males) of Damanhour Teaching Hospital. Study sample included 120 subjects to form 4 groups: gp I (30 normal subjects as control), gp II (30 patients +ve for S. mansoni only), gp III (30 patients seopositive for HCV only), and gp IV (30 patients with mixed S. mansoni and HCV infection). The intensity of schistosomiasis was estimated by Kato-Katz technique. ELISA was used to detect anti HCV, HBs Ag and to estimate interleukin 2 (IL 2) in serum of selected groups. Indirect haemagglutination test was used to detect schistosomiasis among pure HCV. Complete blood picture and liver function tests were also done. Out of 513 samples examined, 89 (17.3%) were +ve for Schistosoma mansoni and 7 (1.4%) +ve for Schistosoma heamatobium. The overall prevalence rate among males was almost double that among females (21.9% versus 12.1%). The risk of HCV infection increased 7 times with the presence of S. mansoni infection. Focusing on the risk factors for S. mansoni infection it was found that gender, water contact, low education, and low socioeconomic status were the most important factors affecting prevalence of S. mansoni infection which in turn increased the risk of HCV infection. In the selected studied groups the results of heamatological and biochemical parameters showed significant decrease in group IV (schistosomiasis + HCV) than that of normal controls, schistosomal, and HCV patients groups. On the other hand, there were an increase in serum bilirubin and aminotransferase enzymes in the group of mixed infections. It has been shown that, in patients with mixed infections, IL2 level was lower than that of the other 3 groups. In conclusion S. mansoni was the predominating species in the present study. History of water contact, low education, and low socioeconomic status were the most important determinant factors of schistosomiasis. The risk of HCV infection increased with the presence of schistosomiasis.