Background: To clarify the role of intention to treat for patients with localized nasal natural killer (NK)/T-cell lymphoma, and to determine the prognostic factors for these patients. Patients and methods: We conducted a retrospective review of 46 patients with localized nasal NK/T-cell lymphomas treated at a single institute between January 1988 and July 2002. Results: The type of intended treatment was a significant factor for overall survival (OS) (5-year OS: RT versus CT = 83.3% versus 28.6%, P = 0.0269) or failure-free survival (FFS) (5-year FFS: RT versus CT = 83.3% versus 27.1%, P = 0.0247). In the intended chemotherapy group, salvage with radiotherapy was superior to chemotherapy alone for OS (5-year OS: 42.2% versus 20.0%, P = 0.0252) or FFS (5-year FFS: 41.0% versus 20.0%, P = 0.0352). On multivariate analysis, both N stage and serum lactate hehydrogenase level were independent factors for OS and FFS. No radiotherapy was an independent adverse factor for OS; advanced T stage and more than one extranodal involvement were independent adverse factors for FFS. Conclusions: Patients with localized nasal NK/T-cell lymphomas were better managed with radiotherapy as front-line therapy. The advantage of radiotherapy persisted even as palliative therapy after chemotherapy.