To test whether Helicobacter species play a role in the enhancement of liver necro-inflammation and fibrosis and in the development of hepatocellular carcinoma (HCC), we sought DNA sequences of Helicobacter species in liver specimens from patients with viral-related chronic hepatitis, HCC or metastatic liver carcinoma. We enrolled 28 consecutive patients with ultrasound evidence of hepatic nodule(s) on their first liver biopsy: 21 had histological evidence of HCC (Group I) and 7 of metastatic liver carcinoma (Group II). In the same period we observed 27 consecutive patients with chronic hepatitis on their first liver biopsy (Group III). Helicobacter sequences were sought by PCR using primers for the 16S rDNA of Helicobacter spp, designed to amplify a 400 base-pair fragment, and detected by 2% agarose gel and hybridization with a specific biotinylated probe. We used, as positive controls for the DNA extraction from liver tissue, hepatic biopsy sections in which HBV infection was confirmed by HBcAg positivity and in which we amplified HBV-DNA by specific primers; positive controls for the amplification of Helicobacter spp were obtained from gastric biopsy sections in which Helicobacter pylori infection was confirmed by biochemical and histochemical tests. HBV-DNA was found in all five HBcAg positive liver biopsies. Helicobacter spp 16S rDNA was detected in all five biopsy specimens of gastric mucosa and in none of liver specimens from patients in any group. Our data suggest that Helicobacter species were not involved in the pathogenesis of virus-related HCC, chronic hepatitis or liver carcinoma metastasis.