Although men who have sex with men (MSM) comprise an estimated 2% of the overall U.S. population aged≥13 years (1), 59% of persons with diagnoses of human immunodeficiency virus (HIV) infection in the United States in 2009 were MSM, including MSM who inject drugs (2). CDC recommends HIV testing at least annually for sexually active MSM to identify HIV infections and prevent ongoing transmission (3). Results of HIV testing conducted as part of the National HIV Behavioral Surveillance System (NHBS) in 21 cities indicated that 19% of MSM who were tested in 2008 were HIV-positive; of these, 44% were unaware that they were infected (4). To assess whether MSM were tested as recommended and whether more frequent testing might be indicated, CDC analyzed NHBS data for 2008. This report describes the results of that analysis, which indicated that, of 7,271 MSM interviewed and tested who did not report a previous positive HIV test, 61% had been tested for HIV infection during the past 12 months; among these, 7% had a new, positive HIV test result when tested as part of NHBS. Given the high prevalence of new HIV infection among MSM who had been tested during the past year, sexually active MSM might benefit from more frequent HIV testing (e.g., every 3 to 6 months).