We demonstrated the feasibility of collecting and disseminating mid-season estimates of influenza vaccine coverage. We surveyed a nationally representative sample of U.S. adults (n = 3972) via the Internet about use of influenza vaccination as of mid-November 2008. Findings were presented on 10 December 2008 to the media and the public health community during National Influenza Vaccine Week through a webinar sponsored by the National Foundation for Infectious Disease. Survey results suggested that just under 40% of adults with a specific vaccine indication had been vaccinated by mid-November and that 16% still intended to be vaccinated. Among those with the intention to be vaccinated, factors related to time and convenience were cited as reasons for not yet being vaccinated. If reported annually, national-level estimates of mid-season vaccine use could provide a benchmark against which to measure progress of strategies deployed at mid-season to improve influenza vaccination coverage.