In an unselected group of patients with aggressive non-Hodgkin's lymphoma (A-NHL) treated at our institution during a 10-year period (1989-1998), we studied the treatment outcome and influence of possible prognostic factors. Two hundred one patients with A-NHL were analyzed retrospectively with regard to personal, treatment, and disease-specific characteristics. Median age was 55 years (range: 16-87 years) and the male:female ratio was 1.5. During a median follow-up of 26 months, the overall response rate was 74% (complete response 63%, partial response 11%). The 2- and 5-year disease-free survival rates were 49 +/- 3% (mean +/- SEM) and 41 +/- 4%, respectively. In a univariate analysis, the following variables were associated with prognosis in terms of survival: patient age, clinical stage, performance status, B symptoms, erythrocyte sedimentation rate, treatment response, and histologic grade of tumor. In multivariate analyses, patient age, performance status, and treatment response emerged as independent prognostic factors for survival.