The therapeutic outcome of chemotherapy in NK/T cell lymphoma (NTCL) has not been well documented until now. The aims of this study were to investigate the outcome of chemotherapy and to evaluate the clinical factors influencing the responsiveness to chemotherapy. Between 1995 and 2000, 59 patients received anthracycline-based chemotherapy as an initial treatment. Forty-five patients had nasal NTCL, whereas 14 had extranasal NTCL. Forty-one patients had stage I/II and 18 had stage III/IV disease. Epstein-Barr virus status was positive in 67.6% of cases. The results of initial chemotherapy were complete remission in 35.6% of the patients, 2-year disease-free survival in 22.9% and 2-year overall survival in 44.2%. Adjuvant radiotherapy after chemotherapy did not improve outcome in stage I/II nasal NTCL. The International Prognostic Index was a significant prognostic factor of complete remission rate, and stage was also significant for disease-free survival.