Primary Sjögren's syndrome is a chronic systemic rheumatic disease characterized as an autoimmune exocrinopathy or autoimmune epithelitis thereby suggesting a pathogenesis leading to tissue specific autoimmune lesion. The development of internationally approved criteria for the classification and diagnosis of Sjögren's syndrome has been a major scientific task for nearly two decades with consensus now approaching. In contrast, an international dialogue on how to develop additional common criteria for the assessment of disease activity, organ damage and outcome in Sjögren's syndrome has just recently been initiated. Such assessment criteria would provide useful measures for patient management and are mandatory for comparing efficacy between different clinical trials. The lack of common assessment criteria may be explained by missing uniform diagnostic criteria, by the multispeciality and systemic nature of the disease and the difficulties in separating out what is activity and what is damage in Sjögren's syndrome. Attempts are now made to overcome these problems. The purpose of this paper is to give a brief introduction to the concepts of disease activity, damage and outcome in Sjogren's syndrome with reference to the results obtained from a recent workshop on assessment tools in Sjögren's syndrome held in Oxford, England in March 2000.