BACH2, a B cell-specific transcriptional repressor, plays a significant role in B cell maturation. Despite a number of previous studies, the clinicopathological significance of BACH2 expression in diffuse large B cell lymphoma (DLBCL) remains to be established. The present study was performed to validate the significance of BACH2 expression as a predictor of prognosis in DLBCL. A total of 94 DLBCL cases were included in the present study. All were diagnosed between 2008 and 2011, and thorough clinical and pathological investigations were possible, including immunohistochemical analysis of BACH2. Eighteen cases were selected by positive MYC gene alteration (MYC+ group) according to cytogenetic study. The remaining 76 cases were subclassified into germinal center B cell phenotype (GCB group, 38 cases) or non-GCB phenotype (non-GCB group, 38 cases). There were no significant differences between the two groups with regard to clinical characteristics and outcomes. In the GCB group, 21 cases were judged to have high BACH2 expression, with 19 cases in the non-GCB group. In cases with high BACH2 expression in GCB and non-GCB groups, the 3-year overall survival (OS) rate was significantly shorter than that with low expression (71.7% vs 91.3%, P = 0.0256). In the MYC+ group, 15 cases had high BACH2 expression levels. Although overall the MYC+ group showed short survival time (3-year OS 35.0%), 3 out of 4 cases with low BACH2 expression are alive without disease relapse at the time of publication of this paper. In conclusion, BACH2 expression level is a promising predictor of prognosis for DLBCL.