After joint arthroplasty, the risk of deep vein thrombosis and pulmonary embolism increases exponentially. Inadequate anticoagulation prophylaxis may not sufficiently reduce the risk of thrombosis, whereas excessive anticoagulation therapy may predispose the patient to a bleed. Bilateral adrenal hemorrhage is a relatively rare but potentially catastrophic life-threatening event. An 82-yr-old woman is described who was rehospitalized from a subacute rehabilitation facility complaining of epigastric pain radiating into her flank. Eight days previously, she had undergone an uncomplicated bilateral total knee arthroplasty and was subsequently administered subcutaneous heparin and warfarin. An abdominal computed tomographic scan subsequently demonstrated bilateral small adrenal hemorrhages. Acute adrenal insufficiency (Addison's disease) caused by hemorrhage within the adrenal cortices, although still uncommon, can be expected to increase as anticoagulation prophylaxis after joint arthroplasty becomes routine.