A total of 160 cases of non-Hodgkin's lymphoma were obtained form the file of Department of Pathology, Seoul National University Hospital during a period of 5 years beginning from 1976 to 1980. These tumors were classified according to modified Rappaport and Lukes-Collins classifications. The patient ranged in age from 1 to 84 years, with an average of 36.9 years. One hundred and ten patients were male and 50 were female, and male-to-female ratio was 2.2 : 1. Of 160 cases, 5 cases (3.0%) were nodular lymphoma and 155(96.9%) were diffuse lymphoma. Nodular lymphomas consisted of 4 cases (2.5%) of histiocytic type and 1 case(0.6%) of mixed type. Diffuse lymphomas consisted of 93 cases (58.1%) of histiocytic type, 32 cases (20.0%) of poorly differentiated lymphocytic type, 16 cases (10.0%) of lymphoblastic type, 8 cases (5.0%) of mixed type, 3 cases (1.9%) of undifferentiatiated Burkitt type, 2 cases (1.3%) of undifferentiated pleomorphic type, and 1 case (0.6%) of mycosis fungoides. Cases of nodular poorly differentiated lymphocytic and diffuse well differentiated lymphocytic type were not found. Fourteen of 16 lymphoblastic lymphomas occurred under the age of 20. Nodular type was not present under the age of 20. Analysis of biopsy sites disclosed 69 cases (43.1%) from lymph node and 91 cases (56.9%) of extranoal sites. Most frequent extrandodal site was tonsil, followed by gastrointestinal tract, subcutaneous tissue, oral cavity, nasal cavity and nasopharynx. In summary, the low frequency of nodular lymphoma and extreme rarity (none in this series) of well differentiated lymphocytic lymphoma were confirmed and the most frequent type was diffuse histiocytic lymphoma. Detailed discussion of morphologic characteristics and comparison of Rappaport and Lukes-Colline classifications were done.