Diffuse large B-cell lymphoma (DLBCL) having both t(14;18) and 8q24 translocations is rare. We evaluated the clinical characteristics and prognoses of patients with DLBCL carrying both t(14;18) and 8q24 translocations. A total of 1972 patients with non-Hodgkin's lymphoma were treated in the Adult Lymphoma Treatment Study Group (ALTSG) from 1998 to 2007. Nineteen cases of de novo DLBCL with the dual translocation were identified. The dual translocation was observed in 19 of 394 patients with DLBCL (10 males and 9 females, with a median age of 61 years). The dual translocation was observed significantly more frequently among patients with high lactate dehydrogenase levels, B symptoms, bone marrow involvement and advanced stage. Immunophenotyping was performed and showed DLBCL with a germinal center type in the majority of cases. Progression-free survival and overall survival rates were significantly lower in patients with the dual translocation than in those with other translocation. DLBCL patients with concurrent t(14;18) and 8q24 translocations have very poor prognosis. Even if patients had a complete response to chemotherapy, they subsequently suffered early relapse. In this study, only a few patients received rituximab, and its usefulness could not be assessed. Future studies with larger numbers of patients are required.