BACKGROUND The sharing and reuse of injecting equipment are associated with acquiring infections. Even in countries with large-scale needle and syringe programmes (NSP), injections using cleaned needles/syringes continue. METHOD People who inject drugs recruited through services completed a short questionnaire and provided a dried blood spot sample. Factors associated with injecting using cleaned needles/syringes in 2011-2012 were explored using logistic regression. RESULTS Of the 2283 participants who had injected during the preceding 28 days (mean age 34.5 years, 23% women), 71% had ever been imprisoned and 37% had recently been homeless. Overall during the preceding 28 days, 34% reported injecting with a needle/syringe that had been cleaned, and 36% had shared any injecting equipment. Of those who had shared, 51% reported injecting with cleaned needles/syringes, compared with 24% of those not sharing. In the multi-variable analysis, injecting using a cleaned needle/syringe was associated with: sharing injecting equipment, injecting more frequently, injecting into hands, injecting crack-cocaine, recent abscess/open wound, homelessness, and poor NSP coverage. CONCLUSION The associations suggest that sub-groups are at particular risk. Using a cleaned needle/syringe could be due to issues with managing injecting equipment supply. Policy should promote good injecting equipment management and use of appropriate cleaning methods.