Studies in North America and Europe indicate that the prevalence of blood-borne viruses (BBVs) is elevated in individuals with severe mental illness; there are no comparable data for the UK. We offered routine testing for HIV, and hepatitis B and C in an inner-London in-patient psychiatric unit as a service improvement. Of the patients approached 83% had mental capacity to provide informed consent for testing and 66% of patients offered testing accepted. Although it was not our objective to establish the prevalence of BBVs, 18% of patients had serological evidence of a current or previous BBV infection. We found that offering routine testing in an in-patient psychiatric setting is both practical and acceptable to patients.