Concerns about the risks of HIV infection among drug injectors have eclipsed concerns about the prevalence and transmission of hepatitis, and in particular hepatitis B virus infection. Findings are reported from surveys undertaken with two separate community-recruited samples of drug injectors in London collected in 1992 (n = 505) and in 1993 (n = 507). Anonymized confirmed testing of saliva shows 51.5% of drug injectors in 1992 and 47.9% in 1993 to be antibody positive to the core antigen of hepatitis B virus (anti-HBc). Approximately half of the drug injectors confirmed as anti-HBc positive were unaware that they had been infected with hepatitis. Anti-HIV-1 prevalence was considerably lower at 7.0% in 1992 and 6.9% in 1993. Multivariate analyses showed anti-HBc positivity to be most likely among older injectors with longer injecting careers who had a history of having shared used needles and syringes. HIV-1 positivity was also associated with a history of having shared injecting equipment as well as with recent sharing (i.e. in the last 6 months). Unlike anti-HBc positivity, there were no associations between HIV-1 positivity and age or length of injecting career. Younger injectors with shorter injecting careers were more likely to report recent sharing of used injecting equipment than older injectors with longer injecting careers. We note the potential for continued transmission of HBV and HIV-1, particularly among younger injectors. We recommend an integrated strategy to maximize the health of drug injectors, of which HIV and HBV prevention is a part. There is a need to widen the availability of HBV vaccinations for HBV negative drug injectors and their sexual partners and for clear guidelines to drug injectors about the relative efficacy of bleach to disinfect injecting equipment of HBV and HIV.