While overall growth in numbers of new HIV infections has slowed in most regions of the world, infections linked to injection drug use (IDU) continue to grow. This trend has been most pronounced in Eastern Europe and Central Asia; however, new infections related to injection drug use also appear to be growing in East Africa. A team from the CSIS Global Health Policy Center recently visited Kenya and Tanzania to better understand the dimensions of the IDU-driven HIV epidemic in those two countries and to look at how U.S.-supported programs through PEPFAR are helping shape a response. The team concluded that recent changes in U.S. policy are playing an important role in helping to improve HIV prevention and IDU treatment policies in both countries and recommended a number of additional measures to ensure that these programs achieve maximum impact.