Seventy-six ambulatory patients with systemic lupus erythematosus and a comparison group of 23 ambulatory patients with rheumatoid arthritis were given a structured interview and standard psychological tests, including the Minnesota Multiphasic Personality Inventory, to determine the psychosocial impact of the illness. Both groups had significantly elevated scores on 3 Minnesota Multiphasic Personality Inventory scales: Hypochondriasis, Depression, and Hysteria. Psychological difficulties are an integral part of systemic lupus erythematosus and are as common as most other manifestations. The implications for clinical practice are discussed.