In January 2011, the Food and Drug Administration lowered the approval age range for use of MenACWY-CRM (Menveo, Novartis Vaccines and Diagnostics), a quadrivalent meningococcal conjugate vaccine, to include persons aged 2 through 55 years. One other quadrivalent meningococcal conjugate vaccine, MenACWY-D(Menactra, Sanofi Pasteur), is licensed in the United States for prevention of meningococcal disease caused by serogroups A, C, Y, and W-135 among persons aged 2 through 55 years; MenACWY-D also is licensed as a 2-dose series for children aged 9 through 23 months. The Advisory Committee on Immunization Practices (ACIP) recommends that persons aged 2 through 55 years at increased risk for meningococcal disease and all adolescents aged 11 through 18 years be immunized with meningococcal conjugate vaccine. ACIP further recommended, in January 2011, that all adolescents receive a booster dose of quadrivalent meningococcal conjugate vaccine at age 16 years. This report summarizes data supporting the extended age indication for MenACWY-CRM and the interchangeability of the two licensed meningococcal conjugate vaccines.