People who are incarcerated have a disproportionately high risk of HIV infection. Prisoners are at risk for infection with HIV because of the association of injection drug use with incarceration. They also tend to have risk components associated with under-utilization of antiretroviral therapy such as substance abuse, mental illness, and poor access to care. Women prisoners who have practiced prostitution, which is often associated with injection drug use and contact with HIV-infected sex partners, are at additional risk for HIV infection. For many inmates, the behaviours and situations that contributes to the HIV infection are those which leads to their incarceration. For others, infection with HIV occurres during incarceration via sex or sharing needles. Counter to the critical need for health care interventions and prevention efforts in correctional facilities have a direct impact on the health of the communities to which prisoners return.