Diffuse large B-cell non-Hodgkin's lymphoma (LDCGB) is one of the best examples of chemotherapy curable malignant diseases. This "Oncoguía SEOM" summarizes the basic directions of staging and recommended treatment options. The staging study should be thorough and includes clinical, laboratory, diagnostic imaging and nuclear medicine. Treatment depends on patient characteristics and comorbidity and on disease extension and prognostic factors. In localized cases, chemoimmunotherapy (CHOP-R) of short duration, followed by involved-field irradiation is the preferred option. In advanced stages, the association of CHOP-like chemotherapy and Rituximab has been a major breakthrough in terms of cure rate. It is important do not forget the supportive treatment in these patients.