Systemic lupus erythematosus (SLE) is an autoimmune disease that can significantly impact both physiological and psychological functioning. In order to examine the relationship between psychological functioning and disease activity in SLE, we administered instruments that collected sociodemographic information and measured indices of disease activity and psychosocial functioning from 125 adult Hispanic and White patients with SLE. Patients were recruited from four healthcare settings in the greater Southern California area. Both cross-sectional and longitudinal relationships between depression and disease activity were evaluated. Cross-sectional findings revealed that depression and ethnicity were independently correlated with self-reported disease activity. Longitudinally, depression alone predicted self-reported disease activity. These data suggest that depression may play a significant role in the health status of SLE patients and serve as an important target for clinical intervention.