OBJECTIVE: Early identification of patients with rheumatoid arthritis (RA) is essential to allow the prompt institution of therapy. The 2010 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) classification criteria, which replace the 1987 classification criteria, have been developed to facilitate such identification in patients with newly presenting inflammatory arthritis. This study therefore assesses the performance of these new criteria in patients with early synovitis. METHODS: Data were analysed from patients with synovitis seen within 3 months of the onset of inflammatory arthritis. Patients were followed for 18 months to determine outcomes, and data on the cumulative fulfilment of 2010 and 1987 criteria and therapy were recorded. RESULTS: 265 patients were included in the study. 60 had alternative diagnoses at baseline. Of the remaining 205 patients, 20% fulfilled both 1987 and 2010 criteria, 3% fulfilled only 1987 criteria and 22% fulfilled only 2010 criteria at baseline. The 2010 criteria, when applied at baseline, detected more patients who eventually required disease-modifying antirheumatic drugs (DMARD) (65 (62%) vs 40 (38%); p The 2010 ACR/EULAR criteria allow more rapid identification of patients requiring methotrexate compared with the 1987 ACR criteria when applied at baseline. However, overdiagnosis is an important issue to consider if these criteria are to be used in very early disease.