Anamorsin is a cell-death-defying factor, which was originally isolated as a molecule that conferred resistance to apoptosis induced by growth factor starvation. In order to evaluate anamorsin expression levels in malignant lymphoma, we immunostained paraffin-embedded sections with anti-anamorsin monoclonal antibodies. About 40% (89/234) of sections from patients with diffuse large B cell lymphoma (DLBCL) showed strong anamorsin expression. Comparing the level of anamorsin expression in DLBCL patients with their clinical features (i.e., overall survival rate, International Prognostic Index (IPI) parameters, and treatment response) revealed no significant correlation between anamorsin expression levels and these clinical features. However, anamorsin expression in DLBCL patients with a low IPI was shown to be an unfavorable biomarker, especially in the patients who received chemotherapy without rituximab. It is suggested that anamorsin might play some roles in the abnormal growth of DLBCL.