Aims: To explore the influence of social relationships, at the interpersonal and community level, on safer and unsafe drug use practices among injection drug users (IDUs) in Nova Scotia, Canada. Method: Thirty-eight current injection drug users were recruited through two needle exchange programs. Fifteen women and 23 men participated in semi-structured interviews about their daily lives, relationships and safer/unsafe drug use and sexual practices. Findings: Most participants were well aware of the risks associated with injecting drugs and reported purposely engaging in numerous strategies to minimize those risks for themselves and others. However, several IDUs revealed that the dynamics of their relationships with other IDUs and with non-IDUs could and did lead to unsafe practices including needle sharing. Stigmatizing encounters with non-users and social exclusion from mainstream resources and structures appear to underlie and reproduce these unsafe practices. Conclusions: Within the current Canadian political context, there is a move to shift drug policies away from harm reduction toward a more enforcement-based approach. This shift will likely only exacerbate the current discourse of blame and stigma directed at injection drug users. In addition, it may serve to increase the interdependency among IDUs, and social and economic exclusion from non-IDUs.