Effective treatment of active rheumatoid arthritis (RA) requires early diagnosis and early disease modifying antirheumatic drug (DMARD) treatment to have an impact on long term morbidity and mortality. Clinical criteria would facilitate early referral of the patient with suspected RA to a rheumatologist for definitive diagnosis and initiation of DMARD treatment at that point in the disease most likely to have an impact on the long term outcome. To develop a referral recommendation that may serve as a clinical guide for primary care doctors, enabling them to identify patients with suspected RA during the early inflammatory stages. Key points of the referral criteria were formed based on a thorough literature review targeting early RA, early arthritis clinics, DMARD treatment for early RA, prognostic factors of disease progression, early RA clinical trials, and quality of life. Evidence was graded using the methods defined by Shekelle et al. A draft version of the criterion was circulated among the authors for critical evaluation. A consensus integrated these comments. Clinical evidence strongly supports the observations that structural damage occurs early in active RA and that early DMARD treatment improves the long term outcome of the disease. The observations indicate that rapid referral to a rheumatologist is advised when RA is suspected. This may be supported by the presence of any of the following: >or=3 swollen joints, metatarsophalangeal/metacarpophalangeal involvement, and morning stiffness of >or=30 minutes. The proposed early referral recommendation is a viable tool for primary care doctors to identify potential patients with active RA early in the disease. Early referral to a rheumatologist for definitive diagnosis and early DMARD treatment should improve the long term outcome of RA.