Hepatitis C virus (HCV), a member of the genus Hepacivirus in the Flaviviridae family, is a single-stranded RNA virus that infects humans and other higher primates and has a selective tropism to the liver. Although the HCV particle itself is difficult to demonstrate, by inferring from the virions of other Flaviviridae, the putative particle is composed of a nucleocapsid composed of the core protein and viral RNA, surrounded by a phospholipid membrane in which the viral envelope proteins are embedded. The replication cycle of the HCV can be divided into stages: binding and entry into the cell; polyprotein translation and processing; RNA replication; and packaging, assembly, and release of the virion. The current recommendations for disinfecting reusable endoscopic equipment by mechanical washing with detergent and soaking in 2% glutaraldehyde were shown to be sufficient to eliminate contamination with HCV. Hepatitis C can be transmitted vertically from mother to child. Successful eradication of hepatitis C with antiviral treatment significantly reduces, but does not eliminate completely, the risk of chronic hepatitis C (CHC). Serologic assays for detecting HCV infection were rapidly developed and improved following the initial discovery of the virus because of the urgent need to screen blood donors and prevent transmission. In general, antiviral treatment is indicated for any adult patient with CHC who is viremic and has elevated aminotransferases or histologic evidence of progressive liver disease, i.e., fibrosis extending beyond the portal tracts.