PURPOSE OF REVIEW: Key populations at high risk for HIV acquisition and transmission, such as MSM, have long been identified as essential subpopulations for epidemiological surveillance of the HIV epidemic. However, surveillance systems in the context of generalized and widespread HIV epidemics have traditionally excluded these men. RECENT FINDINGS: Emerging and consistent data highlight the disproportionate burden of HIV among MSM that exists when compared with other men of reproductive age across countries with generalized epidemics. Correlates of prevalent HIV infection include individual-level determinants of HIV acquisition and transmission similar to that found in concentrated HIV epidemics and community-level structural factors, such as stigma, being blackmailed, and history of homophobic abuse. HIV incidence was only available from two countries (Kenya, Thailand) with generalized HIV epidemics, but in both settings was an order of magnitude higher than that of other populations. SUMMARY: The data presented here suggest that the dynamics of HIV infection among men are more similar across the world than they are different. Many HIV epidemics among average-risk reproductive age adults are slowing across both generalized and concentrated settings. It is in this context that high HIV incidence is observed among MSM, especially young MSM. This trend suggests a change in the trajectory of these HIV epidemics, a change that we may miss if we continue to understudy these populations based on unproved and dated assumptions.