Several studies have reported a higher prevalence of hepatitis C virus (HCV) infection in patients with B-cell non-Hodgkin's lymphoma (NHL) than in the general population. Treatment for NHL includes the use of chemotherapeutic agents such as cytotoxic drugs, corticosteroids, and rituximab, which can be immunosuppressive and hepatotoxic. While reactivation of hepatitis B virus (HBV) when undergoing immunosuppressive therapy for haematological malignancies is a well-documented complication, data on HCV reactivation or liver function impairment after chemotherapy for NHL are controversial. From January 2006 to December 2009, 207 consecutive NHL patients treated with chemotherapy without rituximab (CHOP) or with rituximab (R-CHOP) were observed; screening for HCV infection and baseline liver function tests were performed in all patients. The prevalence of HCV infection was 9.2%. This prevalence is higher than that observed in the general population in Italy (3%). Among the HCV-infected subjects, the incidence of hepatitis flares was 26.3% vs 2.1% among the HCV-uninfected individuals. Although less frequent and less severe than in HBV-infected subjects, liver dysfunction can occur as a consequence of rituximab-containing regimens in HCV-infected patients with NHL. In the cases considered in this study, no patient treated with chemotherapy without rituximab developed hepatitis flares. The frequency and the severity of this complication vary in different reports. Therefore, we recommend the assessment of liver function and the screening of all patients with NHL for HCV infection before starting chemotherapy; we also recommend monitoring of liver function tests and HCV-RNA serum levels during treatment.