The French Hospital Database on HIV (FHDH) is a hospital-based multicentre open cohort with inclusions ongoing since 1989. The research objectives focus mainly on mid- and long-term clinical outcomes and therapeutic strategies, as well as severe AIDS and non-AIDS morbidities, and public health issues relative to HIV infection. FHDH also serves to describe HIV-infected patients receiving hospital care in France. FHDH includes data on more than 120 000 HIV-infected patients from 70 French general or university hospitals distributed throughout France. Patients are eligible for inclusion if they are infected by HIV-1 or HIV-2 and give their written informed consent. Standardized variables are collected at each outpatient visit or hospital admission during which a new clinical manifestation is diagnosed, a new treatment is prescribed or a change in biological markers is noted, and/or at least every 6 months. Since its inception, variables collected in FHDH include demographic characteristics, HIV-related biological markers, the date and type of AIDS and non AIDS-defining events, antiretroviral treatments and the date and causes of death, as reported in the medical records. Since 2005, data have also been collected on: co-infection with hepatitis B or C virus; alcohol and tobacco use; and non HIV-related biomarkers. Anyone can submit a research project by completing a standardized form available on the FHDH website (http://www.ccde.fr/_fold/fl-1385734776-429.pdf) or from the corresponding author, describing the context and objectives of the study. All projects are reviewed by the scientific committee.