In winter 2001, we quantified exposure to HIV medication direct-to-consumer advertising and its relationship to attitudes and behaviors among sexually transmitted disease clinic attendees. We found that homosexual men frequently saw HIV medication advertisements. HIV-positive homosexual men with greater advertisement exposure believed HIV was a less serious disease. Men believed these advertisements influenced an individual's decision to have unprotected sex. HIV-positive homosexual men with greater advertisement exposure may be more likely to have unprotected anal intercourse.