In spite of all recent years' international meetings, the question of diagnostic criteria of primary Sjögren's syndrome (pSS) is still under debate. The aim of our study is to define sensitivity, specificity and diagnostic accuracy of 3 sets of criteria: those of the European Community Study Group (ECSG), those proposed by Fox, and those proposed by Daniels. We considered 219 subjects complaining of dry mouth and/or dry eyes and/or parotid swelling, evaluated for pSS. The following parameters were considered golden standard for the diagnosis of pSS: focus score > or = 2 foci/mm2, double positivity for SSA and SSB antibodies, and a sialographic grade > or = 2. Our study demonstrates that ECSG criteria show a high sensitivity and a good specificity, resulting in a diagnostic accuracy similar, and sometimes higher, than that obtained with Fox and Daniels' criteria.