In the United States, chronic hepatitis C virus (HCV) infection affects an estimated 3 million persons, most younger than 50 years of age. It is one of the leading causes of chronic liver disease morbidity and mortality and the most common indication for liver transplantation. Effective treatment can eradicate the virus and eliminate or reduce liver inflammation and fibrosis, and counseling and immunization can modify or prevent the adverse effect of cofactors (for example, alcohol consumption or co-infections) on disease progression. However, controversy surrounds the need to routinely identify asymptomatic HCV-infected persons. Because no data currently demonstrate that treatment or other interventions will reduce future cases of HCV-related chronic disease and deaths, the U.S. Preventive Services Task Force found insufficient evidence to recommend for or against routine screening for HCV infection in adults at high risk. Chronic hepatitis C would require many years of follow-up to determine the incidence of complication after treatment of or other interventions in asymptomatic persons. It seems inappropriate to wait several decades to measure the impact of early identification of this viral infection when current data support a positive therapeutic effect that points to long-term benefits. In addition, treatment and other interventions must be provided before cirrhosis or liver failure occurs. Therefore, medical and public health professionals should continue the practice of screening persons for risk factors; offering testing to those at increased risk for HCV infection; and providing infected persons with appropriate counseling, medical evaluation, and treatment.