The Advisory Committee on Immunization Practices (ACIP) consists of 15 experts in immunization and related fields, selected by the Secretary of the U.S. Department of Health and Human Services, to provide advice and guidance on control of vaccine-preventable diseases. In its role as a federal advisory committee, the ACIP develops written recommendations, subject to approval of the Director of the Centers for Disease Control and Prevention, for administration of U.S. Food and Drug Administrationâ€“licensed vaccines to children, adolescents, and adults in the U.S. civilian population. On the basis of careful review of available scientific data, including disease morbidity and mortality in the general U.S. population and in specific risk groups, vaccine safety and efficacy, cost-effectiveness, and related factors, the ACIP recommends vaccines and age for vaccine administration, number of doses and dosing interval, and precautions and contraindications. The ACIP works closely with several liaison organizations, including the American College of Physicians, to develop immunization recommendations that are harmonized among key professional medical organizations in the United States. This report includes a description of the member composition of the ACIP, the degree to which Committee members are screened for conflicts of interest, the workgroups that gather information before full Committee consideration, and the process and types of evidence used to formulate recommendations.