The presentation, severity and prognosis of rheumatoid arthritis (RA) differ depending on the age of disease onset. Elderly onset RA (EORA: age of onset > 60 years) has been reported to differ from younger-onset RA (YORA) by a more balanced gender distribution, a higher frequency of acute onset often associated with systemic features, more frequent involvement of the shoulder girdle and higher disease activity. To add to our knowledge of this disease, 101 EORA and 88 YORA patients, not previously treated with DMDARs or steroids, were studied and compared, paying particular attention to the onset. The female to male ratio was higher in the YORA group (4.4:1 vs 1.6:1; p < 0.05). The disease duration was similar: 5.6 +/- 3.3 months in EORA and 7.9 +/- 3.8 months in YORA. EORA presented a more frequent acute onset (33.6% vs 13.6%; p < 0.05) especially if rheumatoid factor was absent. This subset also showed more frequent polymyalgic onset. Constitutional symptoms (fever, weight loss, fatigue) were more frequent in EORA patients without differences between seropositive and seronegative patients. The distribution of involved joints showed a significantly higher frequency of shoulder involvement in EORA (64% vs 38%; p < 0.05) and of feet involvement in YORA (25% vs 52%; p < 0.05). Hands and wrists were the most frequently involved joints in all patients.