Viral hepatitis and its acute and chronic complications continue to pose significant threats to the readiness of military personnel. Knowledge about the specific viral agents and their routes of transmission are important in developing prevention strategies. A recent analysis of hepatitis in the US Navy for the period 1975-1984 is reviewed. In order to better characterize the risk of viral hepatitis among US Air Force personnel, a comprehensive review of inpatient and quarters data for hepatitis A, B and 'non-A, non-B' were reviewed from Air Force medical treatment facilities worldwide for the period 1980-1989. Following a discussion of the study methodology, preliminary data and hepatitis type-specific demographic risk variables are discussed. Preliminary results from a hepatitis serosurvey (A, B and C antibody with use of a supplemental validating assay) of the subset of the study cohort who are currently on active duty are briefly reviewed.