The aim of this study was to investigate if age at disease onset comprises a separate parameter for disease expression, prognosis, and outcome in early rheumatoid arthritis (RA) patients. Four hundred thirty-eight patients with early RA (disease duration less than 1 year) were studied. All of them fulfilled the American College of Rheumatology criteria for RA. The demographic, clinical, laboratory, radiologic, and therapeutic characteristics of the disease at diagnosis and during and at the end of follow-up (time period 1981-2000) were analyzed according to age at disease onset (young patients aged less than 60 years at disease onset vs elderly patients aged more than 60 years at disease onset). We found 317 young and 121 elderly patients with early RA. The male:female ratio, which was 1:3.2 in the young patients, was nearly equal in the elderly (1:1.4). In addition, at disease onset elderly patients showed more severe joint involvement (decreased grip strength) associated with high titers of acute phase response (erythrocyte sedimentation rate and C-reactive protein) than the younger patients. However, there were no differences between the two groups in the numbers of tender and swollen joints or acute phase response at the end of the study period. Furthermore, no differences were seen between the two groups concerning the presence of rheumatoid factor. Finally, the two patient groups showed the same degree of radiological changes and functional ability and were treated similarly, except for more frequent corticosteroid use in the elderly. We conclude that elderly patients present with more severe joint involvement at disease onset. However, at the end of the study, no differences were seen concerning radiological changes and functional ability. It seems that age at disease onset does not influence the clinical course and outcome of early RA patients.