We determined the hepatitis C virus (HCV) antibodies (anti-HCV) and the hepatitis B virus (HBV) surface antigen (HBsAg) in a cohort of 68 consecutive non-Hodgkin's lymphoma (NHL) patients diagnosed and treated in our institution between December 1997 and March 1999. 27 cases were diagnosed as low-grade, 33 as intermediate-grade, and eight as high-grade NHL. In 35 cases (51.4%) we found evidence of either HCV or HBV infection. Anti-HCV antibodies were found in 20 patients (29.5%) and HBsAg was found in 21 patients (30.8%). In six patients both anti-HCV and HBsAg were present. Anti-HCV were present in 12/27 low-grade NHL cases (44.4%) and in 8/41 intermediate/high-grade (aggressive) NHL cases (19.5%, P < 0.03). HBsAg was found in 10/27 low-grade NHL cases (37%) and in 11/41 aggressive NHL cases (26.8%). Evidence of liver disease, as reflected by elevated aminotransferases or typical alterations at liver biopsy, was present in eight patients. Cryoglobulins were present in six patients, all anti-HCV positive and with low-grade NHL. The prevalence of both HCV antibodies and HBsAg was significantly higher (P < 0.0001) in our NHL cases than in a sample of the general Romanian population, where the prevalence of anti-HCV was 4.9% and that of HBsAg was 6.3%. It is difficult to say whether either HCV or HBV had actually been involved in lymphomagenesis or if alpha-interferon treatment would be effective in this subset of patients.