Emergency departments represent ideal settings for vaccination efforts because each year millions of adults who have no or limited access to traditional primary care visit hospital EDs for medical and surgical problems that are non-life threatening. Such EDs often already provide other medical screening and preventive care services in the management of their patients. Almost one-quarter of adults aged 65 years and older make one or more visits to an emergency department each year. Patients who use EDs as their usual source of care are more likely to be members of minority groups and uninsured. These characteristics suggest that vaccination programs in EDs could have a significant impact in correcting disparities in vaccination coverage among patients in older age groups.