Acute pericarditis as a presenting sign of adrenal insufficiency is rarely reported. We present a rare case that highlights pericarditis as a clinical presentation of secondary adrenal insufficiency later complicated by cardiac tamponade. A 44-year-old lady who presented to the hospital with a one-day history of pleuritic chest pain and shortness of breath. In the emergency room, she had a blood pressure of 70/35 mmHg. Laboratory evaluation revealed white blood cell count of 16.08 k/cumm with neutrophilia, normal renal function and elevated troponin (0.321 ng/mL, normal 0.000-0.028). An electrocardiogram (EKG) showed sinus tachycardia, low voltage, PR suppression and ST changes consistent with acute pericarditis. Echocardiogram showed small pericardial effusion without tamponade physiology. Infectious workup was negative; she was thought to have acute adrenal insufficiency likely secondary to viral pericarditis. We treated the patient with high dose nonsteroidal anti-inflammatory drugs (NSAIDS) and hydrocortisone. Three weeks later, she presented to emergency room with complaints of persistent nausea, vomiting, chills, weakness. Her blood pressure was 49/23 mmHg. Random serum cortisol level was <1.2 mcg/dl (normal A.M. specimens 3.7-19.4 mcg/dl). Echocardiogram showed loculated pericardial fluid adjacent to the right ventricle with echocardiographic evidence of tamponade. Emergent pericardiocentesis yielded 250 ml of straw color fluid. Blood pressure improved after the procedure. The patient was initially started on IV stress dose steroids, but following clinical stabilization, hydrocortisone was switched to a physiological dose of 15 mg in am and 10 mg in pm. Although the mechanism of pericarditis in adrenal failure is unknown, this clinical presentation may help early diagnosis of adrenal failure and pericarditis. Early recognition and prompt treatment of this rare presentation are critical to prevent morbidity and mortality.