The health and social consequences of intravenous drug use pose major challenges to cities across North America. Preventable drug-related harms including accidental overdose, serious bacterial infections, injuries of violence and more recently, the emergence of HIV and hepatitis C, have major impacts on community health. Among the various interventions designed to reduce the harms associated with injection drug use, the establishment of a supervised injection facility is perhaps the most controversial. This review will focus on the potential impact of supervised injection facilities on HIV transmission in conjunction with current HIV prevention initiatives. This will include a review of the health and social consequences associated with illicit drugs use, the limitations of drug enforcement, and the potential impact of supervised injection facilities on reducing the harms associated with injection drug use.