The introduction of highly active antiretroviral therapy (HAART) has led to dramatic reductions in morbidity and mortality due to HIV infection. However, the resulting optimism and improved health status produced by HAART appears to have contributed to unanticipated consequences in men who have sex with men (MSM): loss of fear of acquiring and transmitting HIV, an increase in high-risk sex, decreased use of condoms, and a resurgence of gonorrhea and syphilis. Other factors, such as lack of knowledge of sexually transmitted diseases (STDs), use of the Internet as a venue to find sex partners, the increasing use of Viagra (Pfizer, New York, NY) as a recreational drug, and the apparent expanding role of oral sex in STD transmission are fueling these trends. Since ulcerative and inflammatory STDs facilitate HIV transmission, a new wave of HIV infection in MSM may be on the horizon. The rising STD rates and relapses in high-risk sexual behaviors in MSM, both HIV-infected and -uninfected MSM, have profound implications for public health and the clinical management of these patients. Clinicians should be aware of this turn of events, and implement new screening and counseling guidelines that have been issued in response to these alarming reports.