Joint damage and disability in rheumatoid arthritis (RA) both increase with disease duration but the nature of their relationship is uncertain. This review updates knowledge of the progression and inter-relationship of joint damage and disability in treated RA and provides a synopsis of the main predictive factors for damage and disability. In early RA 39-73% of patients develop one or more erosions in their hands and wrists by 5 years. In established RA the average annual increase in radiological damage scores is 1.9% maximal damage. After 20 years RA patients have on average 43% of maximum possible damage. These data suggests that joint damage progresses constantly over the first 20 years of RA. The average annual increase in HAQ scores is 0.033 per year (1% of possible maximum disability). In the first years of disease there is a "J-shaped" curve with an initial fall in HAQ scores followed by an increase over the next four years. In cross-sectional studies there is either no correlation or a weak correlation between damage and disability in early RA; this absence of correlation is explained by the "J-shaped" curve of disability with disease duration in early RA. As disease duration increases the correlation between damage and disability becomes more obvious; 9 studies show correlation coefficients between 0.31 and 0.75. The most predictive factors of damage and disability are rheumatoid factor status and disease activity. The validity of our conclusions are limited by the potential indirect link between small joint damage and disability, with large joint damage being a more important predictor, and the presence of ceiling effects on X-rays. In conclusion, joint damage accounts for a substantial proportion of the disability associated with the disease.