The purpose of this study was to evaluate the outcome and prognostic factors of patients with limited stage follicular non-Hodgkin's lymphoma treated prospectively by the Nebraska Lymphoma Study Group (NLSG). Forty previously untreated patients, median age 64 years, with limited stage follicular lymphoma were prospectively treated according to the protocols of the NLSG between January 1980 and December 1990. The follicular large cell type represents 75% of the cases, and 14 of the biopsies also had a diffuse component (composite lymphoma). The initial treatment was radiation therapy (RT) to the involved field in 15 patients, anthracycline-containing combination chemotherapy (CT) in 20, and combined RT and CT in 5. Thirty-seven patients (92.5%) achieved a complete remission (CR). The median follow-up is 120 months (range, 20 to 214). Of the 37 patients achieving a CR, 7 patients are alive in first CR, one died due to sepsis, another because of a myeloproliferative disorder at 77 months following chemotherapy, 6 died because of unrelated causes in first CR. Twenty-two patients relapsed between 1 to 128 months following a CR. The estimated 10-year event-free survival is 21% (95% CI: 7 to 35). Two patients received no or palliative therapy after relapse and both died of progressive disease. Nineteen patients received salvage therapy and 15 achieved a second remission. The median survival after first relapse is 55 months. The estimated 10-year overall survival is 44% (95% CI: 28 to 60). Various factors including sex, histologic subtype, stage, and degree of follicularity do not influence the overall survival or event-free survival. CT with or without RT resulted in a better trend for 10-year event-free survival in stage IA patients compared to RT alone but estimated 10-year overall survival is no different. The overall survival is worse in the > or = 60 age group but this difference is not evident if data is adjusted for cause specific death. In conclusion, limited stage follicular lymphoma has an excellent initial response to radiation therapy or chemotherapy; however the recurrence rate is high and cure is limited.