There is only limited information on the prevalence and influence of coinfection with either hepatitis B or C on the clinical course in patients infected with the human immunodeficiency virus (HIV). Samples of 232 HIV infected patients were investigated for markers of HBV and HCV infection (HBsAg, HBeAg, Anti-HBs, anti-HBc, anti-HCV, HCV-RNA). 60/232 patients (23%) were anti-HCV positive. 78% of these sera were positive for HCV-RNA. 22/232 patients (9%) suffered from chronic HBV-infection (HBsAg positive), 18/22 (82%) of these sera had detectable HBeAg. Presence of HCV-RNA, HBeAg was related to the degree of immunodeficiency. In patients with AIDS coinfection with HBV or HCV was associated with a reduced survival compared to controls (HBV: 212 days, 95% CI, 106 to 317; HCV: 267, 95% CI, 112 to 396; controls: 439 days, 95% CI, 364 to 513). Coinfection of HIV and HBV or HCV is frequently observed. Our results suggest that in HIV-infected patients with AIDS coinfection with either HBV or HCV was associated with a reduced survival rate.