Thyrotoxicosis is a life-threatening disorder when encountered after a major surgical procedure. Plasma exchange is an occasionally reported alternative treatment to thyroidectomy, iodine ablative therapy, or the administration of thyreostatic drugs. We used plasmapheresis as a lifesaving treatment in a patient with thyrotoxicosis, as encountered after a left-sleeve pneumonectomy, in whom many classic therapies either failed or were not retained.