This study addresses the disproportionate representation of men who have sex with men (MSM) in the human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) pandemic in Kazakhstan, a country that has seen some of the largest growth in new HIV infections since the turn of the century. Using a stepped wedge trial across 4 cities in Kazakhstan, the proposed study will test a strategic and innovative social network-based intervention for MSM who use drugs in Kazakhstan as a strategy to increase their numbers in the HIV continuum of care as well as services that address issues that co-occur with HIV, including drug abuse, Hepatitis C Virus (HCV) infection, and other sexually transmitted infections.