A randomized clinical trial was performed to evaluate a psychological treatment intervention and a social support program, compared with a control program in which no adjunct treatment was rendered, and their effects upon pain behavior, affect, and disease activity of 53 patients with rheumatoid arthritis. The psychological intervention produced significant reductions in patients' pain behavior and disease activity at posttreatment. Significant reductions were also observed in trait anxiety at posttreatment and 6-month followup. Relaxation training may have been the most important component of the psychological intervention. The social support program produced a significant reduction in trait anxiety only at posttreatment. This is the first well-controlled study to demonstrate reduced pain behavior, disease activity, and trait anxiety following psychological treatment.