A total of 352 cases of non-Hodgkin's lymphoma reported to the Cancer Registry of Northern Sweden during 1978-1982 were retrospectively analysed. After morphologic review, 327 cases classifiable as low (n = 162) or high-grade (n = 165) according to the Kiel classification remained for further study. The purpose of the study was to evaluate the interrelations between some variables and their bearing on prognosis in an almost unselected clinical material. Age, morphological grade of malignancy, clinical stage, systemic symptoms, bulk of disease and serum lactate dehydrogenase (LDH) level turned out to be associated with the clinical outcome in terms of response to treatment, disease-free survival and survival. In the heterogenous group of low-grade lymphoma, six pretreatment characteristics were negatively associated with survival in a univariate analysis, namely; stage II-IV, systemic symptoms, bone marrow infiltration, two or more extranodal sites, elevated LDH and age above 65 years. In high-grade lymphoma, stage II-IV, bone marrow infiltration and elevated LDH predicted a worse prognosis in a multivariate analysis. The impact of the number of these prognostic factors on survival in high-grade lymphoma was demonstrated.