The serological status for both hepatitis B, C and D viruses was analyzed for 500 HIV seropositive patients and for 1037 of a control group. The prevalence was 31.4% for anti HCV, 13.8% for HBs Ag and 69.0% for one or more HBV markers in HIV positive patients and respectively 2.5%, 2.7% and 13.1% in control group. The markers for hepatitis D were founded among 21% of the HBs Ag carriers (patients and control group), correlated with drug i.v. use. The prevalence of anti-HCV was 71.6% in subjects who had blood-borne HIV infection and 1.5% in those with sexually acquired infection. The prevalence in control group was 10.2% and 1.7% respectively according to the same risk factors. The prevalence of HBs Ag was higher among HIV positive patients with sexual risk (17.5%) than with blood exposition (9.9%) and a variation in the same direction is observed in control group (3% v.s. 1%). The relation between markers for hepatitis B and hepatitis C was negative.