Five hundred seventy lupus erythematosus patients observed in a private practice between 1980 and 1989 were surveyed. Fifty-five percent were diagnosed after 1980. Five hundred three fulfilled criteria for systemic lupus erythematosus ( [SLE]; 464 idiopathic, 23 overlap, 16 drug-induced) and 67 had biopsy-documented cutaneous (discoid) lupus. In the idiopathic SLE group, symptoms began at a mean age of 31 years and patients were observed for a mean of 6 years. Findings in idiopathic SLE patients were (1) 27% have a family history of autoimmune disease; (2) nephritis patients without nephrotic syndrome rarely develop renal failure (4%); (3) nephrotic syndrome patients are relatively cyclophosphamide-resistant; (4) organ-threatening disease is present in 54%; and (5) 13% of women who become pregnant are recurrent aborters and 26% never conceive. In an analysis of cohort data, 5- and 10-year survivals were 97% +/- 2% and 93% +/- 3%, respectively. Additionally, men and patients with renal disease or thrombocytopenia had a poorer prognosis. Blacks had similar clinical findings and survival to whites. Approximately 50% of deaths were from active disease and 50% from complications of therapy. Prolonged survival has resulted from new diagnostic procedures and serologic tests, and improved antibiotics and antihypertensive agents, as well as more efficacious treatment modalities.