Prognostic factors, including clinical, biological, and histological parameters, were assessed for 94 patients with follicular lymphomas at our institute. Follicular lymphomas constituted 7.7% (94/1208) of malignant lymphomas in this study. Eighteen patients were diagnosed with stage I follicular lymphoma, 20 with stage II, 23 with stage III, and 33 with stage IV. The cases of follicular lymphoma were subclassified as: follicular small cleaved cell lymphoma (FSC) in 20 cases, follicular mixed cell lymphoma (FMX) in 59 cases, and follicular large cell lymphoma (FLC) in 15 cases. The patients comprised 49 men and 45 women with a median age of 54 years (range, 25-84 years). The complete response rate was 76.5%, and the median survival time was 13 years. The expected 10-year overall survival and event-free survival rates were 61.9% and 38.2%, respectively. Univariate analysis identified the factors associated with poor survival as elevated serum lactate dehydrogenase (LDH) level (P < .0001), age of >60 (P < .0001), Ann Arbor stage III/IV (P < .01), and Eastern Cooperative Oncology Group performance status (PS) of 2 to 4 (P = .048). Multivariate analysis showed that LDH, age, and PS were independent predictors. After application of the International Prognostic Index (IPI), the 10-year survival rates for the low-risk, low-intermediate risk, high-intermediate risk and high-risk groups were 80.4%, 48.7%, 21.9%, and 0.0%, respectively. The differences among these groups were significant at P < .01. The IPI for aggressive non-Hodgkin's lymphoma was found to be applicable to survival prediction for Japanese follicular lymphoma patients.