Introduction: Combination of interferon-alpha (IFN-α) and Ribavirin (RBV) drugs is used for treatment of hepatitis C virus (HCV) chronic infection. Various factors play role in the response rate of HCV infected patients to treatment. HCV genotype along with viral load, age, race, obesity, insulin resistance, fibrosis and interleukin 28B gene (IL-28B) polymorphisms are considered the most important ones. In recent years, it has been claimed that some polymorphisms close to IL-28B gene play a significant role in response to combined therapy among which IL-28B polymorphisms have a more important role in sustained virological response (SVR). In this study, frequency of genotypes of rs8099917 polymorphism of interleukin 28B gene in 2 groups of Iranian healthy individuals and HCV infected patients living in Tehran was compared.
 
Materials & Methods: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to compare the frequency of genotypes of rs8099917 polymorphism between 105 healthy individuals and 105 chronic HCV infected patients. The results were analyzed with SPSS version 15 using χ2 test.
 
Findings: The genotype frequency of this polymorphism in the healthy individuals was demonstrated as GG: 1%, GT: 25.7% and TT: 73.3%, while in HCV infected patients, it was shown as GT: 58.1% and TT: 41.9%.. No GG genotype was detected in the patients infected with HCV.
 
Discussion & Conclusion: Our investigation came to the conclusion that  a significant difference existed between the 2 groups of Iranian healthy and HCV infected individuals regarding the frequency of rs8099917 genotypes and frequency of favorable TT genotype, because it was higher among the healthy individuals than that of the patients infected with HCV