BACKGROUND Adrenal crisis is a life threatening condition which can be induced by stress during surgery in patients with adrenal insufficiency. This may be prevented by perioperative administration of high doses of steroids. There is disagreement on whether supplemental perioperative steroids are required and, when administered, on the amount and frequency of doses. OBJECTIVE To assess whether it is necessary to administer supplemental perioperative steroids in adult patients on maintenance doses of glucocorticoids because of adrenal insufficiency. METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, Issue 1); MEDLINE (1966 to January 2009); EMBASE (1980 to January 2009); LILACS (1982 to January 2009); and the databases of ongoing trials. We handsearched the Journal of Clinical Endocrinology and Metabolism (1982 to 1997), Clinical Endocrinology (1972 to 1997), Surgery (1948 to 1994), Annals of Surgery (1948 to 1994), and Anaesthesia (1948 to 2000). METHODS Randomized, controlled trials that compared the use of supplemental perioperative steroids to placebo in adult patients on maintenance doses of steroids who required surgery. METHODS Two review authors independently assessed trial quality and extracted data. Study authors were contacted for missing information. We used mean differences and standard deviations to summarize the data for each group. RESULTS Two trials involving 37 patients were included. These studies reported that supplemental perioperative steroids were not required during surgery for patients with adrenal insufficiency. Neither study reported any adverse effects or complications in the intervention and control groups. CONCLUSIONS Owing to the small number of patients, the results may not be representative. Based on current available evidence, we are unable to support or refute the use of supplemental perioperative steroids for patients with adrenal insufficiency during surgery.