Background: Viral hepatitis C is an important global health problem that affects about 2.2% of humans. Strategies on the control of this hepatotropic virus focused on chemotherapy and surveillance of emerging HCV drug resistant mutants, respectively. HCV genotype 1 response to therapy is one of major interests. The aim of this research was to study the prevalence of resistant associated variants (RAVs) in the naive HCV patient candidate for direct acting antiviral (DAA) therapy. Methods: A total of 70 HCV confirmed patients which referred to hospitals affiliated to Iran University of Medial Sciences, Tehran, Iran from May 2014 to March 2015 were enrolled in this cross sectional study. After RNA extraction, RFLP-RT-Nested-PCR was performed for HCV genotyping, then some genotypes 1 and 3 strains were used for further amplification of NS5B gene S282T mutation site and purified products were sequenced. Bioinformatics software was used for analysis of sequences. Results: From a total of 70 HCV patients, 54 were male (mean age (y)+/- SD 35.1 +/- 8.2) and 16 were female (mean age (y)+/- SD 43.4 +/- 10.1); 26 isolates from 1 a, lb and 3a showed that there were no S282T resistant mutants. Moreover, 2 (4.8%) had a synonymous point mutation (C to T). Statistical analysis didn't found any significant correlation between age, sex and genotype variables. Conclusion: Finally, it can be concluded that there were no resistant mutants in our HCV genotypes 1 and 3 infected patients and broader scale of studies are required in this area using larger specimens, genotype groups and stages of treatment. (C) 2017 Published by Elsevier Ltd.