Annual influenza vaccination for health care workers has the potential to benefit health care professionals, their patients, and their families by reducing the transmission of influenza in the health care setting. Furthermore, staff vaccination programs are cost-effective for health care institutions because of reduced staff illness and absenteeism. Despite international recommendations and strong ethical arguments for annual influenza immunization for health care professionals, staff utilization of vaccination remains low. We have analyzed the ethical implications of a variety of efforts to increase vaccination rates, including mandatory influenza vaccination. A program of incentives and sanctions may increase health care worker compliance with fewer ethical impediments than mandatory vaccination.