This report updates the 2006 recommendations by CDC's Advisory Committee on Immunization Practices (ACIP) regarding the use of influenza vaccine and antiviral agents (CDC. Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices [ACIP]. MMWR 2006;55[No. RR-10]). The groups of persons for whom vaccination is recommended and the antiviral medications recommended for chemoprophylaxis or treatment (oseltamivir or zanamivir) have not changed. Estimated vaccination coverage remains <50% among certain groups for whom routine annual vaccination is recommended, including young children and adults with risk factors for influenza complications, health-care personnel (HCP), and pregnant women. Strategies to improve vaccination coverage, including use of reminder/recall systems and standing orders programs, should be implemented or expanded. The 2007 recommendations include new and updated information. Principal updates and changes include 1) reemphasizing the importance of administering 2 doses of vaccine to all children aged 6 months--8 years if they have not been vaccinated previously at any time with either live, attenuated influenza vaccine (doses separated by > or =6 weeks) or trivalent inactivated influenza vaccine (doses separated by > or =4 weeks), with single annual doses in subsequent years; 2) recommending that children aged 6 months--8 years who received only 1 dose in their first year of vaccination receive 2 doses the following year, with single annual doses in subsequent years; 3) highlighting a previous recommendation that all persons, including school-aged children, who want to reduce the risk of becoming ill with influenza or of transmitting influenza to others should be vaccinated; 4) emphasizing that immunization providers should offer influenza vaccine and schedule immunization clinics throughout the influenza season; 5) recommending that health-care facilities consider the level of vaccination coverage among HCP to be one measure of a patient safety quality program and implement policies to encourage HCP vaccination (e.g., obtaining signed statements from HCP who decline influenza vaccination); and 6) using the 2007--2008 trivalent vaccine virus strains A/Solomon Islands/3/2006 (H1N1)-like (new for this season), A/Wisconsin/67/2005 (H3N2)-like, and B/Malaysia/2506/2004-like antigens. This report and other information are available at CDC's influenza website (http://www.cdc.gov/flu). Updates or supplements to these recommendations (e.g., expanded age or risk group indications for currently licensed vaccines) might be required. Immunization providers should be alert to announcements of recommendation updates and should check the CDC influenza website periodically for additional information.