Cost effectiveness analyses of alternative hepatitis B vaccination programmes in England and Wales require a robust estimate of the lifetime risk of carriage. To this end, we report the prevalence of infection in 3781 anonymized individuals aged 15-44 years whose sera were submitted in 1996 to 16 microbiology laboratories in England and Wales. One hundred and forty-six individuals (3.9%) were confirmed as anti HBc positive, including 14 chronic carriers (0.37%). The prevalence of infection and carriage was higher in samples collected in London and increased with age. No increased risk of infection was seen in sera from genito-urinary (GUM) clinics. Only 15 sera positive for hepatitis B were also positive for hepatitis C. Our results confirm the low prevalence of hepatitis B in England and Wales, are consistent with previous estimates of carriage and suggest that many infections were acquired while resident outside the UK. Future prevalence studies should determine the country of birth and other risk factors for each individual in order to confirm these findings.