Our retrospective followup study reports the outcome of rheumatoid arthritis (RA) in relation to age (under 60 vs 60 years and over) and rheumatoid factor status at diagnosis. A sample of 130 adult patients with RA was assessed at a mean of 5.6 years after diagnosis. At final evaluation disease activity and radiographic damage in seropositive patients were similar in both age groups, but functional capacity was markedly lower in the older onset group, indicating lower functional reserves in this group. In seronegative patients the outcome was favorable in both age groups, especially in the older patients. Seropositive patients in both age groups had more disease activity, a lower functional capacity and more radiographic damage than seronegative patients; these differences were greater in the older onset patients. The mortality in patients with RA compared to the general population (standardized mortality ratio, SMR) was higher in seropositive patients (SMR 2.78, 95% CI 1.70-4.13) but not in seronegative patients (SMR 0.45, 95% CI 0.08-1.13). The relative risk of dying was 6 times higher in seropositive patients than in seronegative patients (95% CI 1.7-20.9).