People in prison have multiple complex health and social care needs. These are likely to be the result of a combination of overlapping, and sometimes interlinked, risk factors for infection, ill-health, and incarceration, such as problem drug use. Incarceration can represent a unique opportunity to make high-quality health care available to people in prison and to target socially deprived groups who are often medically underserved when living in the community they originate from. In recent years, international and European institutions have increasingly acknowledged the importance of treating prison health as an inseparable component of public health.