Pituitary apoplexy is a rare but potentially life-threatening condition caused by the sudden enlargement of a pituitary adenoma secondary to infarction and hemorrhage. The clinical syndrome is characterized by sudden onset of headache, ocular palsies, visual disturbances, and altered state of consciousness. We report 2 patients who had postoperative pituitary apoplexy after total hip and total knee arthroplasty. Asymptomatic pituitary adenomas are difficult to diagnose preoperatively. Its existence is an unlikely suspect until the clinical symptoms develop after surgery. This is the first reported case following total hip arthroplasty.