This study examined the degree to which depression is related to physical and psychosocial dysfunction. The Beck Depression Inventory and the Sickness Impact Profile were administered to 34 patients with rheumatoid arthritis. Information on the demographic variables (age and employment status) and medical status variables (duration of disease and functional classification) were collected for each patient. Regression analyses revealed that depression was an important predictor of total, physical and psychosocial sickness-related behavioural dysfunction. The proportion of variance attributed to depression was moderate to large and was significant even after controlling for important demographic and medical status variables. These results suggest that depression is an important factor to be considered when evaluating the clinical significance of physical and psychosocial dysfunction in patients with rheumatoid arthritis.