Nasal NK/T cell is a rare form of usually localized non-Hodgkin's lymphoma (NHL) which generally carries a poor prognosis when treated with conventional NHL chemotherapy protocols. We reviewed 20 consecutive localized stage I/II nasal NK/T cell lymphomas treated at our institution over a 29 year period. Median age was 44 (range 23-71). Front-line therapy was generally radiotherapy alone (35-70 Gy) before 1980 and combination chemotherapy after 1980. Six patients were treated with first-line radiotherapy and they achieved complete remission (CR). Two subsequently received combination chemotherapy. Five of those patients remained in complete remission, after 97+ to 277+ months. Twelve patients were treated with first-line chemotherapy including CHOP or CHOP-like regimen in seven cases, and COP in five cases. Only three of them achieved CR, five had partial response and four had progressive disease. Five of the seven patients treated with CHOP did not achieve complete remission. The nine patients who failed to achieve CR with chemotherapy subsequently received salvage radiotherapy but only two of them obtained CR. Finally, two patients were treated with alternated chemotherapy and radiotherapy and achieved CR, which persisted after 14+ and 26+ months. Median survival was not reached in patients who received front-line radiotherapy, and was 35 months in patients who received front-line chemotherapy. These findings confirm that chemotherapy gives a low complete remission rate in localized nasal NK/T cell lymphoma. By contrast, first-line radiotherapy seems to give favorable results, whereas its results are poorer when administered after resistance to chemotherapy. Whether the use of chemotherapy after radiotherapy, or alternated chemotherapy-radiotherapy regimens give better clinical results than radiotherapy alone will have to be evaluated prospectively in this type of NHL.