To determine whether the analysis of lymphocyte surface markers provides clinically useful information, neoplastic cells from 51 adult patients with NHL were studied for surface markers and phagocytosis. The analysis revealed that NHL could be classified into four types according to the neoplastic cell type; T-cell, B-cell, Null-cell and true histiocyte types. On the basis of this immunofunctional classification, response to chemotherapy and survival of the patients were evaluated. The chemotherapeutic responsiveness rate (CR+PR rate) and complete remission (CR) rate of the T-cell type were shown to be the lowest in stage III and IV patients. Especially in stage IV, the CR rate of the T-cell type was statistically the lowest. Patients in both stages III and IV of the B-cell type survived the longest and those of the T-cell type, the shortest. In stage IV, the survival period of the T-cell type NHL patients was significantly shorter than those of the non-Burkitt B-cell type or Null-cell type. However, the difference between the survival of the B- and Null-cell types was not clear. These results indicate that the immunofunctional classification is some what useful for prediction of chemotherapeutic response and prognosis in NHL.