Beclin 1 plays an important role in autophagy, differentiation, antiapoptosis and the development and progression of cancer. The function and expression of Beclin 1 in natural killer T-cell lymphoma is largely unexplored. The study aimed to investigate Beclin 1 expression and its relationship with prognosis in extranodal natural killer T-cell lymphoma, nasal-type (ENKL). Beclin 1 protein expression in 65 tumor specimens from patients newly diagnosed with ENKL was examined by immunohistochemistry (IHC). The clinical significance of Beclin 1 in ENKL was statistically analyzed. Immunopositivity for Beclin 1 was found in 56 (86.2%) of the 65 samples. Low Beclin 1 expression was significantly associated with advanced Ann Arbor stage, intermediate to high IPI risk and elevated LDH level. Low Beclin 1 expression was associated with worse overall survival (OS; p = 0.001) and progression-free survival (PFS; p = 0.017). In multivariate analysis, Beclin 1 expression, advanced Ann Arbor stage and B symptoms were found to be independent prognostic factors of OS and PFS. Consequently, a new clinico-pathological prognostic model was proposed. The model could discriminate different survival outcomes between low risk and high risk groups based on OS and PFS (p < 0.0001, respectively). Beclin 1 expression is predictive of prognosis in ENKL. The new clinico-pathological prognostic model may be help identify patients with different clinical outcomes. © 2010 Landes Bioscience.