This report clarifies the prognostic factors for survival in localized non-Hodgkin's lymphoma (NHL) of the head and neck and defines optimal regimens for this disease. One hundred-seven untreated patients with Stage I or II NHL of the head and neck were treated with involved field radiation therapy for orbital, nasal, or paranasal lymphoma and extended field radiation for Waldeyer's ring or neck lymphoma. Radiation doses were 39-48 Gy. In the latter half of the study, adjuvant chemotherapy was administered. Of 107 patients, 95 achieved complete response (CR). Of the 12 patients that did not achieve CR, 9 had nasal T-cell lymphoma (NTL) of the lethal midline granuloma type (LMG-NTL). Only one patient who obtained CR relapsed in a previously irradiated area. Age, sex, stage, bulky mass, number of involved sites, LMG-NTL, histologic subtypes, radiation dose, and adriamycin dose were analyzed for prognostic significance for disease-specific survival in NHL by multivariate analysis. LMG-NTL was the most significant prognostic factor (P < 0.001). Patients with higher age also experienced a higher relative risk than patients of > or =60 years of age (P = 0.0063). Dose of adriamycin reached the borderline significance (P = 0.0600). Radiotherapy is excellent for obtaining local control of head and neck NHL. Randomized trials are required to determine the appropriate radiation field and dose in patients previously treated with chemotherapy. LMG-NTL and age were the significant prognostic factors for disease-specific survival.