Background: Activation of pathway of nuclear factor kappaB (NF-κB) which is caused by genetic alterations has been reported in B cell lymphoma. A20 gene is considered main regulator component of NF-κB signaling. Its function is mainly suppression of this pathway. Deletions and/or mutations in A20 gene cause inactivation of this pathway which were found in various hematologic malignancies. Objective: The current study aims to determine the prevalence of A20 gene mutations and their relationship with the clinical and laboratory profile in diffuse large B-cell lymphoma (DLBCL). Patients and methods: A total 100 DLBCL patients were investigated for A20 gene mutation by real time polymerase chain reaction. Results: A20 gene mutation GA mutant genotype was found in 18% of the patients, where 77.8% of them were ABC-DLBCL subtypes. GA heterozygous genotype was frequently associated with stage IV and extra-nodal infiltration, and shorter overall survival (OS). Conclusion: Our study suggests a role of A20 gene mutation in DLBCL pathogenesis as well as its prognosis.