Non-Hodgkin's lymphoma of the nasal cavity and paranasal sinus is not common because the major site of head and neck lymphoma. To understand the clinical and pathological characterisitics of malignant lymphoma, the authors retrospectively reviewed the medical records, X-ray films, and pathological specimens of 13 cases of extranodal malignant lymphoma developed in the nasal, paranasal sinus and nasopharynx. The patients' age was evenly distributed in the range between 11 and 80 years. Presenting symptoms were nasal obstruction in 7 cases(53%), rhinorrhea in 3 cases(23%), orbital swelling in 2 cases(16%), and earfullness in 1 case(8%) in the order of decreasing frequency. According to the Working Formulation, the commonest histopathologic type was diffuse large cell type in 9 cases(69/%), and the others were diffuse mixed small and large cell type(1 case, 8%), diffuse small cleaved cell(1 case, 8%), and unconfirmed(2 cases, 15%). Combination of chemotherapy and radiotherapy was given to 9 patients(69%), and only chemotherapy was given to 4 patients(31%). Treatment outcomes of 8 cases, who were followed up for more than 12 months, revealed that 3 patients(37%) with stage III or IV died with disease. Our study suggests that early diagnosis using punch biopsy for the patients with suspicious symptoms and physical finding is mandatory to improve the prognosi of sino-nasal malignant lymphoma.