BACKGROUND: Hepatitis vaccination is recommended in patients with chronic liver disease. AIM: To validate Current Procedural Terminology (CPT) codes and drug codes for hepatitis vaccination in administrative databases and determine vaccination rates in hepatitis C virus (HCV)-infected patients in a single large Veterans Administration Medical Center. METHODS: We calculated predictive values for hepatitis vaccination codes in a validation set of 168 patients. We then conducted a retrospective cohort study of 243 HCV-infected patients to determine rates of hepatitis vaccination and serological testing. RESULTS: The presence of CPT or drug codes for hepatitis A vaccine yielded a positive predictive value (PPV) and negative predictive value (NPV) of 93.2% and 94.0%. The presence of hepatitis B vaccine codes yielded a PPV of 98.0% and an NPV of 94.0%. Among patients diagnosed with HCV between 2000 and 2005, receipt of hepatitis vaccination was documented in approximately 8% overall and 7% in patients with cirrhosis. Half of the patients without hepatitis vaccinations were either not tested for immunity or had negative serology. CONCLUSIONS: Current Procedural Terminology or drug codes for hepatitis vaccinations in administrative data are highly predictive of the presence of vaccinations in medical records. Our data suggest that there is significant under-utilization of vaccination in patients with HCV.