This document is the report of the consultation meeting "Prevention and Treatment of HIV/AIDS Among drug Using Populations: A Global Perspective" held in Washington, D.C: on January 11-12. The overarching goal of the meeting was to advance understanding of the global HIV and substance abuse epidemics and highlight the importance of including drug abusers - particularly injection drug users (IDUs) - in any comprehensive, multidisciplinary approach to HIV prevention and treatment. It also was intended to spur progress on the development of comprehensive, integrated approaches that combine addiction treatment with prevention and treatment of HIV and co-infections. The report contains 6 chapters: 1) Introduction; 2) Global Strategy for HIV and Drug Use; 3) Comprehensive Approaches to HIV Prevention for People Who Use Drugs; 4) Expanded HAART to Improve Individual and Public Health Outcomes; 5) Drug Abuse, HIV/AIDS, and the Criminal Justice System: Challenges and Opportunities; and 6) Human Rights and At-Risk and Vulnerable Populations.