Ninety cases of node‐based non‐Hodgkin's lymphoma in northwestern Kyushu, Japan were classified according to the Japanese Lymphoma Study Group (LSG) and the immunological as well as clinicopathological studies were performed. There were 6 cases of small cell type, 23 of medium‐sized cell type, 25 of large cell type, 20 of pleomorphic type, 10 of lymphoblastic type and 6 cases of specific lymphomatous lesions (Lennert's lymphoma and T‐cell lymphoma with angioimmunoblastic lymphadenopathy‐Iike pattern). Immunologically, the T‐cell character was predominant in pleomorphic type (100%), specific lymphomatous lesions (100%), medium‐sized cell type (80%) and large cell type (60%). Clinically, leukemic manifestation was frequently encountered in all histological types except for large cell type. The leukemic cells in pleomorphic type and T‐medium‐sized cell type were polymorphic, similar to those of adult T‐cell leukemia. Skin lesions were found chiefly in leukemic cases of pleomorphic and T‐medium‐sized cell types, and non‐leuke‐mic cases of T‐large cell type. The worst prognosis was observed in the pleomorphic type, especially of leukemic form. These results support the proposal of pleomorphic type as a distinct entity in prospecting the immunological subtype, clinical manifestations, and survival. In addition, T‐medium‐sized cell and pleomorphic types, having common clinicopathological characteristics, may be categorized as one group. On the other hand, T‐large cell type seems to be composed of heterogenous groups of the peripheral T‐cell tumor, although som