Background and Aims: Chronic hepatitis C is one of the most important etiologies of cirrhosis and hepatocellular carcinoma worldwide. Clinical condition of hepatic patients and the outcome of chemotherapy are under impact of Hepatitis C virus (HCV) genotypes. Therefore, HCV genotyping is important for prediction of success of chemotherapy and progression of liver diseases.

Methods: In this article the distribution of HCV genotypes detected in a population in Ahvaz, southwest of Iran is reported. This was a study on 80 patients suffering from chronic hepatitis C.  Following extraction of the viral ribonucleic acid (RNA) patient’s sera, from it was used as the template for the synthesis of complementary deoxyribonucleic acid (cDNA). The amplified fragments of HCV cDNAs by nested PCR were subjected to restriction enzyme analysis. Restriction Fragment Length Polymorphism (RLFP) was performed on all HCV isolates to determine the subgenotype.

Results: Out of 80 HCV positive samples 43 (53.8%) were genotype 1a and 37 (46.2%) were genotype 3a. The dominant genotype of HCV isolated from patients suffering from chronic hepatitis C in Ahvaz was genotype 1a. Therefore, interferon therapy may not help some of these patients against HCV infection.

Conclusion: It is suggested to perform HCV genotyping prior to interferon therapy. Besides, the result suggests that the major route of HCV infection in Ahvaz population is the use of contaminated syringe.