Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease with variable outcomes. In this study, data of 84 DLBCL patients, who were tested EBV DNA in peripheral blood, were retrospectively analyzed. Patients were divided into three subgroups according to EBV copy number (EBV-CN) values: the negative (<500 copies/ml), low (500-10(4) copies/ml), and high EBV-CN group (>= 10(4) copies/ml). The higher EBV-CN was associated with male and elderly patients. No significant difference was found between the three subgroups regarding immunophenotype, cytogenetic features, and molecular features. Patients of the high EBV-CN group had significantly worse progression-free and overall survival (OS) compared to other groups. After adjusting conventional risk factors, high EBV-CN was an independent prognostic factor for OS in multivariate analysis. Taken together, peripheral blood EBV-CN can predict outcomes of patients with DLBCL and 10(4) copies/ml is a more suitable boundary value than the traditional normal value in predicting prognosis.