Compared with the general public, people in prison have a higher prevalence of infection with HIV, hepatitis B, hepatitis C, syphilis, gonorrhoea, chlamydia and tuberculosis. Such increased prevalence of diseases among people in prisons is recognised as a major risk for the health of both people living and working in prison settings and for the general population, as the vast majority of people in prisons return to their communities after less than 24 months of incarceration. According to the principle of equivalence of care, people in prison should enjoy an equivalent standard of care as in the community. Yet, their health needs tend to be greater. Incarceration may thus represent a unique opportunity to make adequate healthcare services available to people and target groups that usually are hard to reach.