Background: Hepatitis C Virus (HCV) infection is diagnosed by antibody and RNA based methods. Anti HCV-RNA testing based methods are introduced to confirm viremia in seropositive samples. This study aimed to evaluate the relationship between quantitative anti-HCV (S/CO ratio) and HCV-RNA by PCR as a diagnostic test to identify viremic from non-viremic HCV patients received anti-HCV therapy in Egypt. Subjects and Methods: Patients serum samples used in this study were collected from Al Hussein University hospitals after they had completed their anti-HCV therapy. A total of 172 patients were included in this study 82 were positive RNA, 90 of them were negative RNA their serum samples were assessed for the presence of antibodies to HCV using ELISA method. Results: The results were expressed as the ratio between the signal detected on the sample and the cutoff value of the run (S/CO). Patients with HCV-positive RNA were considered viremic. Receiver operator characteristic (ROC) curve was constructed by plotting sensitivity versus 1 − specificity, using HCV RNA and the S/CO ratio results respectively. Of the 172 patients with HCV infection the mean age was 51.9 ± 7.2 years ranging 35-67 years, 111 (64.5%) were males while 61(35.5%) were females. In the present study there was significant difference in S/CO ratio between viremic and non- viremic subjects. The sensitivity, specificity, negative predictive value, and positive predictive value were 98.78%, 71.11%, 98.46%, and 75.70%, respectively in the S/CO ratio of 8. Area under ROC curve was estimated to be 0.982 (95% confidence interval 0.967 – 0.997). Conclusion: by establishing 8 as cutoff value of the S/CO, it is possible to distinguish between viremic and non-viremic patients without need to use Anti HCV-RNA testing as a confirmatory test.