Several previous studies have addressed the association between hepatitis C virus (HCV) infection and non-Hodgkin lymphoma (NHL), but there are few studies on HCV-related diffuse large B-cell lymphoma (DLBL). We conducted this retrospective study to investigate the distinctive clinical characteristics and outcome for HCV-positive DLBL. We compared the clinical characteristics and outcomes of 32 HCV-positive DLBL cases from nine Korean institutions with those of 371 HCV-negative DLBL cases. A higher percentage of HCV-positive DLBL cases were associated with old age (> or = 60) than HCV-negative DLBL cases at diagnosis (59.4% vs. 36.1%, respectively, P = 0.009) and HCV-positive cases were less likely than HCV-negative cases to have extranodal involvement (53.1% vs. 71.1%, respectively, P = 0.044). The nodal presentation was the only independent factor favorably influencing the event free survival (EFS) in HCV-positive DLBL (HR = 0.11, 95% CI; 0.01-0.95, P = 0.012). In comparison to patients with HCV-negative DLBL, HCV-positive DLBL patients had a superior complete response rate (P = 0.023) and EFS (P = 0.02). In Korean patients, HCV-positive DLBL is more common with old age and has less extranodal involvement than does HCV-negative DLBL. The superior survival outcome for HCV-positive DLBL should be verified by further investigation, especially with respect to its correlation with transformed low-grade NHL.