To identify the prognostic factors that specifically predict survival rates of patients with localized aggressive non-Hodgkin's lymphoma (NHL), a retrospective study including 118 patients with clinical stage I and 11 NHL treated at the Institute of oncology, Istanbul University between 1989 and 1998 was conducted. Patients were treated either with radiotherapy alone, radiotherapy and adjuvant chemotherapy, or chemotherapy (with or without adjuvant radiotherapy). The 5-year disease-free survival (DFS) and overall survival rates were calculated, and univariate and multivariate analyses were performed to identify the significance of various prognostic factors such as gender, age, performance status, stage (1 versus II), B symptoms, extranodal involvement, gastrointestinal tract disease, erythrocyte sedimentation rate, bulky disease, histologic grade, serum lactate dehydrogenase level, serum beta(2)-microglobulin level, serum albumin level, treatment regimen, remission status, and the International Prognostic Index risk groups, which may have an influence on the outcome of patients with NHL. The overall 5-year survival rate was 52% with a median follow-up of 30 months. The complete response rate was 68%, and the 5-year DFS of complete responders was 70%. Cox multivariate regression analysis showed that incomplete response, low serum albumin, bulky disease (>10 cm), and high grade histology were the pretreatment factors associated with shorter survival. When remission status was included in the model, the attainment of a complete response was the major determinant of long-term survival; however, low albumin level was still a significant adverse predictor for survival in multivariate analysis. These factors need to be evaluated for analyzing the outcome of treatment and to identify better therapeutic strategies.