Over the course of addiction, a substantial proportion of drug users enter drug abuse treatment programs. Data from a cross-sectional survey of drug abuse treatment programs in the United States were analyzed to describe the scope of the medical examination performed at admission to such programs. All of the methadone programs (n=95) and 50% of drug-free programs (80 of 161) required a medical examination at entry. Most examinations included screening for signs and symptoms of liver disease and liver function testing. Nearly all methadone programs (97%) provided referral to medical care or support for patients with test results positive for antibody to hepatitis C virus (HCV), compared with 75% of drug-free programs (P<.01). Drug-free programs requiring medical examinations provided education about HCV and testing for HCV to a larger proportion of their patients (P<.05). With high dropout rates in the early stages of treatment for drug addiction, these medical visits may be an important opportunity for further monitoring and care for HCV infection and other conditions.