BACKGROUND: The prevalence rates of hepatitis B virus (HBV) and hepatitis C virus (HCV) in patients with inflammatory bowel disease (IBD) have been reported to be higher than rates of infection among the general population. Although several cases of HBV infection reactivation in IBD patients treated with anti-TNF-α agents have been described, no evidence exists that anti-TNF-α therapy exacerbates the course of HCV. The aims of this study were to assess the prevalence of HBV and HCV and the rate of HBV vaccination in a population of IBD patients; and to investigate the long-term effects of anti-TNF-α therapy in the subgroup with HBV or HCV infections. METHODS: 301 patients were studied. Prior to the initiation of anti-TNF-α therapy, serum samples were tested for HBsAg and anti-HBc, anti-HBs and anti-HCV antibodies. During the follow-up, HBsAg and anti-HBc positive patients underwent periodic blood testing for viral markers, HBV-DNA and liver function; anti-HCV positive patients were assessed for liver function and HCV-RNA. RESULTS: One patient was HBsAg positive (0.3%), and 22 (7.3%) tested positive for anti-HBc. Seventy-two patients (23.9%) had been vaccinated for HBV. Four patients tested positive for anti-HCV (1.3%). During anti-TNF-α therapy, none of the patients experienced HBV or HCV reactivation. CONCLUSIONS: HBV and HCV infection rates were similar to infection rates among the general population. Less than one quarter of the patients had been vaccinated against HBV. Anti-TNF-α agents appear to be safe for patients with HBV infection; more data are needed for patients with HCV infection.