The spectrum of organ involvement in 50 patients with systemic lupus erythematosus has been assessed in a prospective study. All patients were admitted to hospital electively for 2 days and a complete clinical and laboratory assessment protocol completed. Subsequent hospital admissions depended on clinical status. The overall mean observation period was 29 months. Widespread multisystem involvement was found in every patient. Subclinical abnormalities of respiratory and cerebral function were common even in patients in clinical remission. A more conservative approach than has been generally recommended was used for the management of systemic lupus erythematosus and is supported by the estimated 5-year survival of 98%.