OBJECTIVE: To examine the association of elderly onset rheumatoid arthritis (RA) with health related quality of life in a population based cohort of older women. METHODS: A nested case-control study of elderly onset RA within the Iowa Women's Health Study (IWHS), a prospective cohort established in 1986 of 41,000 women aged 55 to 69 years. A supplemental questionnaire was mailed to 122 RA cases and 1132 frequency matched controls from the cohort. We used unconditional logistic regression and linear regression to examine the association of elderly onset RA with self-reported measures of functional disability and quality of life. RESULTS: Elderly onset RA was associated with a 6-fold risk (OR 6.0, 95% CI 3.6-10.1) of significant functional disability (Health Assessment Questionnaire score (3) 1). Similarly, elderly onset RA was significantly associated with lower physical component scores of the Medical Outcome Study Short Form-12 (37.2 +/- 10.9 vs 43.6 +/- 11.6; p < 0.001). CONCLUSION: Among a community based cohort, elderly onset RA was strongly associated with functional disability and reduced quality of life. These associations were independent of other age associated factors including depression, recent fracture, and multiple comorbidities.