Chronic Hepatitis B (HBV) and Hepatitis C (HCV) virus infections are global health problems which may cause cirrhosis and even hepatocellular carcinoma. Hepatitis D virus (HDV) though a satellite virus of HBV, can also cause chronic infection. Serologic and molecular tools are needed for the diagnosis, monitoring and therapeutic management of chronic viral hepatitis associated with HBV, HDV and HCV. In HBV infection several serological markers are available for diagnosis and staging; while molecular assays are important for pretreatment evaluation, assessing drug response and identification of mutants. The endpoint of chronic HCV and HDV treatment is the sustained virological response, defined by an undetectable HCV/HDV RNA in serum with a sensitive assay 6 months after completion of treatment. HCV genotype and quantitative HCV RNA testing plays an important role in determining treatment duration, doses and also assess the likelihood of treatment response. Thus, virological assays are important in the diagnosis and management of individuals infected with chronic viral hepatitis.