We estimated the prevalence of markers of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection, and injecting risk behaviour, among community-recruited injecting drug users (IDUs) in North West Wales in 2001 and 2002. Sample collection was undertaken by trained current and former IDUs. Oral fluid samples (n = 153) were tested as part of the Unlinked Anonymous Prevalence Monitoring Programme ongoing survey of IDUs. Approximately 12% of the sample reported that they were currently in a drug treatment programme. Of the 153 samples screened 27% (95% CI 20%-34%, 41/153) were anti-HBc positive, and 23% (95% CI 16%-30%, 35/153) were anti-HCV positive. Sixteen per cent (95% CI 10%-22%, 25/ 153) of the samples were positive for both anti-HBc and anti-HCV. Of the subjects 15% (95% CI 9%-20%) knew they had been vaccinated against hepatitis B. Direct sharing of needles and syringes in the 28 days prior to interview was reported by 44% (95% CI 35%-54%), and sharing of any equipment including that used for drug preparation prior to injection was reported by 66% (95% CI 57%-76%). In North West Wales, syringe sharing is a common practice, and a high proportion of IDUs have been exposed to bloodborne viruses. Hepatitis B vaccination coverage within this population appears to be low and needs to be increased. Further efforts are needed to improve the availability of clean injecting equipment.