Immunization rates in the United States still fall short of the Healthy People 2010 goals for children and adults. To improve rates of immunization, physicians need to understand and address barriers to immunization, including fragmented health-care delivery, missed opportunities to vaccinate, and the patient's fear of adverse reactions. This article addresses these issues and suggests strategies by which rates can be improved, such as patient reminders, standing orders, and assessment of and feedback on practitioner performance. Additionally, it provides suggestions to help physicians better communicate vaccine risks and benefits to their patients, potentially affecting an individual's acceptance of those risks. It describes the appropriate use of materials such as the Vaccine Information Statements. Physicians should also be prepared to answer patients' questions about alleged or controversial vaccine adverse events.