Aggressive B cell lymphomas of the gastrointestinal tract include Burkitt lymphoma (BL), diffuse large B cell lymphoma, and B cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL. To investigate the clinical characters of DLBCL/BL of the gastrointestinal (GI) tract, 101 cases of aggressive B cell lymphoma of the GI tract were analyzed by immunohistochemistry and fluorescence in situ hybridization (FISH) using break apart probe for c-MYC gene. For cases with c-MYC rearrangement, additional FISH studies with MYC/IgH fusion probe, BCL2 break apart probe, and BCL6 break apart probe were performed. MYC rearrangement was detected in 23 of 101 cases of aggressive B cell lymphomas (22.5%). The cases with MYC rearrangement were divided into 14 BL, three DLBCL/BL, and six DLBCL. One of the three DLBCL/BL had double translocation for MYC and BCL6 gene. Clinically, DLBCL/BL of the GI tract was more akin to Burkitt lymphoma than it is to GI tract DLBCL with c-MYC rearrangement. The overall prognosis of patients with DLBCL/BL was the worst among aggressive B cell lymphomas. DLBCL/BL is uncommon category of B cell lymphoma in the GI tract with aggressive clinical course despite of intensive chemotherapy.