A 49-year-old woman who had been treated with sodium levothyroxine because of hypothyroidism after diagnosis of Hashimoto thyroiditis and total thyroidectomy for multinodular atoxic goiter was evaluated for persistent hypothyroidism despite the use of large doses of levothyroxine (600 microg/day). The patient showed signs and symptoms of hypothyroidism and her laboratory tests were: TSH of 351 microUI/mL, free thyroxine of 0.20 ng/dL, and total triiodothyronine of 27 ng/dL. She was submitted, under medical supervision, to a levothyroxine overload test with no evidence of malabsorption of the thyroid hormone. Diagnosis of factitious disorder and Munchausen syndrome leading to the pseudomalabsorption of levothyroxine was considered.