Diffuse large-cell and immunoblastic lymphoma (DLCL), considered together, are the most common histologic subtypes of non-Hodgkin's lymphoma (NHL). There will be approximately 15,500 new cases of DLCL in 1995 and this represents a dramatic increase over the last 20 years. The cause of KLCL is unknown, but its association with acquired and inherited immunodeficiency syndromes implicates immune dysregulation as an etiologic factor. Combination chemotherapy is standard treatment for all stages of DLCL. The use of adjutant radiation therapy (RT)_ in stage I-II patients remains controversial, but continues to play an important treatment role. Adjutant RT may permit the use of fewer cycles of chemotherapy and may improve freedom from relapse and survival. The International NHL Prognostic Factors Project has derived a model that helps predict which patients with KLCL will have a poor outcome. This analysis reveals that there are certain early=-stage patients with a poor prognosis who may benefit form more aggressive treatment. This review attempts to provide guidelines for the workup, treatment, and long-term prognosis of patients with early stage DLCL.