The present status of the following aspects of diagnosis and treatment of malignant lymphoma are reviewed, and future directions are discussed. 1. Epidemiology 2. Pathological classification 3. Molecular analysis of oncogenesis and disease progression 4. Staging classification and response evaluation 5. State-of-the art therapy of major subtypes 1) Hodgkin's lymphoma 2) Aggressive non-Hodgkin's lymphoma 3) Indolent B-cell non-Hodgkin's lymphoma 4) Salvage therapy for relapsed cases 6. New agent development focusing on antibody therapy 1) Principles and history of antibody therapy 2) Clinical development of rituximab in the USA and Japan 3) Radioimmunotherapy Recently, the importance of evidence-based medicine has been widely recognized not only by physicians but also by patients themselves. To further improve the therapeutic results, it is extremely important to conduct well-designed clinical trial consecutively.