The association of chronic urticaria and thyroid autoimmunity is not well recognised and the potential use of levothyroxine in the treatment of chronic urticaria in patients with thyroid autoimmunity is even less well known. In addition, there are reports that chronic urticaria remits in some but not all patients who have evidence of thyroid autoimmunity and are treated with levothyroxine. Although the benefical effect of levothyroxine has been proved in chronic urticaria, the mechanism is not known well. In this report, a female patient with an anaphylactic reaction to levothyroxine theraphy has been presented.