To improve our knowledge for future hepatitis A virus (HAV) vaccination strategies we carried out a multicentre study on naturally acquired immunological protection against HAV in patients with chronic hepatitis in Italy. We enrolled 830 consecutive patients with chronic hepatitis on their first observation at one of the six Italian liver units participating in the study. Six hundred and fifty-eight patients (79·3%) were positive for total anti-HAV and 172 (20·7%) were negative. The anti-HAV negative patients were younger (median age 33, range 11–78) than the anti-HAV positive (median age 56, 18–87). There was a higher prevalence of cases with circulating anti-HAV among the 508 patients residing in southern Italy than in the 322 residing in northern Italy (88·8% vs. 64%, P < 0·001). No significant difference in the anti-HAV prevalence was observed between patients from northern Italy and those from southern Italy aged 0–30 years or in those over 60 years, while in those 31–60 years old there was a higher prevalence of anti-HAV positive patients from southern Italy (90·2% vs. 65·8%, P < 0·0001). Of the patients with liver cirrhosis in this study, only 3 of the 26 (11·5%) from northern Italy and 8 of the 228 (3·5%) from southern Italy had no immunological protection against HAV infection. The data suggest that the number of patients with chronic liver disease without naturally acquired immunity against HAV is substantial in Italy, particularly in the north of the country, and that new vaccination strategies are needed.