BACKGROUND: Conventional drug overdose prevention strategies have been criticised for failing to address the macro- and micro-environmental factors that shape drug injecting practices and compromise individual ability to reduce the risks associated with drug-related overdose. This in turn has led to calls for interventions that address overdose risks by modifying the drug-using environment, including the social dynamics within them. Safer injection facilities (SIFs) constitute one such intervention, although little is known about the impact of such facilities on factors that mediate risk for overdose. METHODS: Semi-structured qualitative interviews were conducted with fifty individuals recruited from a cohort of SIF users in Vancouver, the Scientific Evaluation Of Supervised Injecting (SEOSI). Audio recorded interviews elicited injection drug users' (IDU) accounts of overdoses as well as perspectives regarding the impact of SIF use on overdose risk and experiences of overdose. Interviews were transcribed verbatim and a thematic analysis was conducted. RESULTS: Fifty IDU, including 21 women, participated in this study. The perspectives of participants suggest that the Vancouver SIF plays an important role in mediating various risks associated with overdose. In particular, the SIF addresses many of the unique contextual risks associated with injection in public spaces, including the need to rush injections due to fear of arrest. Further, SIF use appears to enable overdose prevention by simultaneously offsetting potential social risks associated with injecting alone and injecting in the presence of strangers. The immediate emergency response offered by nurses at the SIF was also valued highly, especially when injecting adulterated drugs and drugs of unknown purity and composition. CONCLUSION: The perspectives of IDU participating in this study suggest that SIFs can address many of the micro-environmental factors that drive overdose risk and limit individual ability to employ overdose prevention practices. Although challenges related to coverage remain in many settings, SIFs may play a unique role in managing overdoses, particularly those occurring within street-based drug scenes.