This prospective, multicentre study was conducted between September and October 2003 in 38 French departments of internal medicine, infectious disease and hepatogastroenterology and included 406 consecutive HBV-infected patients (positive HBsAg), half of whom were HIV-infected (53%). The aim was to outline the main characteristics of hepatitis B virus (HBV)-human immunodeficiency virus (HIV) co-infected patients in French hospitals. HBV-HIV co-infected patients (85% were receiving HAART; mean CD4 count 447±245/μl, HIV RNA load <400 copies/ml, 67% of patients), compared to HIV-negative patients, were more often male, injecting drug users, HBeAg-positive and HCV-HIV co-infected (P<10−4). They underwent liver biopsy less often (31% vs. 51%, P<10−4), particularly those with severe immunodeficiency. They received anti-HBV treatment more often (75% vs. 45·7%, P<10−4), mainly lamivudine and tenofovir. Significant improvements in the management of such patients are awaited mainly in the appraisal of liver disease by either liver biopsy or non-invasive alternatives to liver biopsy.