Nine of 86 patients with systemic lupus erythematosus (SLE) were diagnosed after the age of sixty. They differ from younger patients with SLE in mode of onset, specific organ systems involved, severity of disease, and prognosis. The presentation in the elderly is insidious rather than acute. Most patients initially show a polymyalgia rheumatica syndrome or rheumatoid-like arthritis. The clinical course is benign, serositis is less common, the patients are more easily controlled on aspirin or low-dose steroids, and the progress of SLE in the elderly is relatively slow. Because age modifies the clinical expression of SLE the diagnosis in the elderly can be easily missed if not specifically searched for.