Significant levels of older-adult mortality and morbidity are associated with vaccine-preventable diseases, specifically influenza and pneumococcal disease. Even though current guidelines for this age group recommend a single vaccination against pneumococcal pneumonia, an annual influenza vaccination and a combined tetanus-diphtheria toxoid booster every 10 years after completion of a primary series, immunization levels remain extremely low. This article presents information regarding usage, efficacy and cost-effectiveness of these vaccines. Physician non-compliance and misinformation, negative patient attitudes and a shortage of effective programs for vaccine delivery account for vaccine underutilization. Recommendations from health care providers significantly affect whether a person will be immunized. Increased vaccine usage was noted in clinic-based programs that initiated organizational or administrative interventions, such as patient and physician reminders, physician-performance feedback, medical-record checklists and the use of non-physician health care staff to monitor patient vaccination status and to dispense vaccines. Providing organized education and vaccination programs in institutional and public settings may also help target the older-adult population. The future success of adult immunization will depend not only on increased professional and public awareness but also on the development of new approaches to vaccine delivery.