Hepatitis delta virus (HDV) is a pathogenic and transmissible virus which requires the helper function of hepatitis B virus for its replication. Epidemiological studies have shown that HDV infection is distributed world-wide, with a higher prevalence in southern areas, especially in Italy. HDV may increase the severity of chronic hepatitis and may be responsible for the fulminant course of this disease. To assess the prevalence and pathogenic role of HDV infection in our geographic area we examined 118 biopsies from HBsAg-positive patients by immunofluorescence microscopy. HDV was detected in 3 biopsies with the histological features of chronic active hepatitis. Our findings show that HDV infection is a rare event among HBsAg carriers in our area.