Hepatitis C virus (HCV) and hepatitis G virus (HGV) belong to the same family of flaviviridea. A causative role of HCV infection in the pathogenesis of non-Hodgkin's lymphoma (NHL) has been discussed widely. Little is known about the possible association between NHL and HGV discovered recently. In this study, anti-HCV and HGV-RNA prevalence were investigated in a group of 70 patients with NHL. The results were compared to a control group of 70 age- and sex-matched healthy subjects. One patient in each group (1.4%) was found to be anti-HCV-positive; the difference was not statistically significant (P > 0.05). Five subjects in the patient group (7.1%) were positive for HGV-RNA, while a single subject was positive in the control group (1.4%); the difference was not statistically significant (P > 0.05). Odds ratios for anti-HCV and HGV-RNA were 1 and 5.30, respectively. Our findings suggest that neither HCV nor HGV are causative or contributing factors in the aetiopathogenesis of NHL.