In a retrospective analysis of 203 patients with non-Hodgkin lymphoma (NHL) treated between 1975 and 1985, the relationship between pathology, clinical presentation and course, was studied, using the Kiel classification. This classification was a much better predictor of prognosis than clinical stage and within the different pathology groups there was no significant difference between the stages concerning the survival rate. In the group with low grade malignancy this latter was positively associated with nodular architecture, bone marrow involvement and complete or partial response to therapy. In the high grade group, the survival was positively correlated to complete remission, but no plateau was seen in the survival curve. All extranodal sites had poor survival. For both grades, age (greater than 60 years), systemic symptoms and biologic signs (Ann Arbor 'B' and 'b') were unfavorable prognostic factors.