INTRODUCTION: The aims of this study were to assess agreement between the currently used 2002 American-European Consensus Group (AECG) classification criteria and the new 2012 American College of Rheumatology (ACR) criteria for Sjogren's syndrome (SS) and to identify potential sources of disagreement. METHODS: We studied 105 patients between 2006 and 2013 from the Brittany cohort of patients with suspected SS. AECG criteria were applied using only Schimer's test and unstimulated whole salivary flow (UWSF) to assess objective ocular and oral involvement, since these are the tests most physicians use in clinical practice. Agreement between the two sets of criteria was assessed using Cohen's kappa coefficient. RESULTS: Of those studied, 42 patients fulfilled AECG and 35 ACR criteria. Agreement between the two sets was moderate (kappa = 0.53). Patients fulfilling ACR but not AECG criteria (n = 8) were significantly younger and had shorter symptom durations, but only three of them had SS in the opinion of the evaluating physician. Xerostomia and xerophthalmia (AECG set only) did not discriminate between patients with and without SS. The use of UWSF in the AECG but not the ACR criteria explained part of the disagreement. The serological item in the ACR set (positive rheumatoid factor and antinuclear antibody >=1:320 or anti-SSA/SSB positivity) did not result in classification differences compared to anti-SSA/SSB antibody alone (AECG set). Agreement between ocular staining score >=3 (ACR set) and Schirmer's test