This study evaluates the prognostic value of MAGE-A3 expression in 28 diffuse large B-cell lymphoma (DLBCL) patients. A significant association was observed between MAGE-A3 expressions, assessed by quantitative real-time RT-polymerase chain reaction (PCR), with advanced stages of disease (P < 0.05). Elevated serum lactate dehydrogenase (LDH) levels and International Prognostic Index (IPI) score were significantly higher in MAGE-A3-positive patients (P = 0.025 and P = 0.004, respectively). Expression of MAGE-A3 was associated with poor response to treatment and a significantly shorter overall survival (P < 0.001). Our data address new information in the association of MAGE-A3 expression and poor prognosis in DLBCL patients.