Adrenal insufficiency, though rare, is a well-known complication of acquired immunodeficiency syndrome (AIDS). Over the past 9 years at the National Taiwan University Hospital, 4 patients were diagnosed with primary adrenal insufficiency among 854 non-hemophiliac patients with human immunodeficiency virus infection, with an incidence of 0.19 per 100 patient-years (95% confidence interval, 0.17-0.21 per 100 patient-years). All of the 4 patients were severely immunosuppressed and had been diagnosed with at least 1 AIDS-defining opportunistic illness ever reported to produce adrenal insufficiency in AIDS patients. In 1 of the patients, fluconazole was considered contributory to the development of adrenal insufficiency after treatment at a daily dose of 800 mg for 68 days.