Syringe sharing places street-involved young people at risk of acquiring HIV and hepatitis C. While markers of economic marginalization, such as homelessness, have been linked with syringe sharing and have led to targeted interventions, the relationship between syringe sharing and other markers of economic vulnerability, such as sex work, are not well documented among young people. This study examines whether those engaged in sex work are at increased risk of syringe borrowing and syringe lending among street-involved youth who use injection drugs in Vancouver, Canada. Between September 2005 and May 2014, data was collected from the At-Risk Youth Study (ARYS), a prospective cohort of street involved youth aged 14-26. Generalized estimating equations with a confounding model building approach was used to examine the relationship between sex work and syringe borrowing and lending. 498 youth reported injecting drugs at some point during the study period and were therefore included in the analysis. In multivariable analysis, youth who engaged in sex work were at an elevated risk of both syringe borrowing (Adjusted Odds Ratio (AOR) = 2.17, 95% Confidence Interval [CI] = 1.40-3.36) and syringe lending (AOR = 1.66, 95% CI = 1.07-2.59). Our study found that youth engaged in street-based sex work were at a significantly higher risk of both syringe borrowing and lending among youth who use injection drugs in Vancouver. Ready access to clean syringes, safer working conditions for sex workers to enable risk reduction measures, and increased access to addiction treatment are identified as promising opportunities for reducing syringe sharing in this setting.