At the Duke University Medical Center, Durham, NC, there are approximately ten recognized hepatitis B virus (HBV) infections per year in employees. The hospital's hepatitis control program costs $91,995 per year, including costs for workman's compensation, hyperimmune globulin, laboratory tests, lost revenue, liability, personnel, and medical treatment. A program to immunize high-risk medical center personnel and to accommodate residual HBV problems in nonimmunized employees would cost $206,304 in the first year. By seven years the cumulative costs of an immunization program would equal those without a program and at ten years would be cost saving ($746,742 with program v $919,950 without a program). Given certain assumptions, HBV vaccine is a cost-beneficial alternative for a major employee health hazard.