Measures taken to reduce HIV risk by injecting drug users have been reported in many countries, but a minority of injectors continue to engage in risky practices. In an ongoing cohort study, 207 drug injectors were interviewed and anonymously tested for HIV antibodies in saliva in 1989. Injectors reporting recent syringe sharing were compared with those not recently sharing; injecting events where sharing did and did not take place were examined. Those recently sharing syringes differed significantly from the non‐sharers on several factors, including: use of heroin, dihydrocodeine and temazepam; injection of heroin, temazepam and prescribed methadone; accommodation and contact with other injectors; means of financial support and recent involvement in crime; secondary sources of injecting equipment and unsafe disposal; employment of HIV protective strategies; treatment contact with general practitioners; number of sexual partners and injecting status of sexual partners. The two groups were not significantly different in terms of attendance at syringe‐exchange schemes and self‐reported HIV antibody status. Syringe sharing would appear to be related to social circumstances and life‐style factors rather than just individual choices and motivation.