Thyroid hormone resistance syndrome, also known as Refetoff syndrome, is a rare disease associated with decreased reaction of body tissues to thyroid hormones (TH). Patients with Refetoff syndrome tend to have elevated free TH concentrations and normal or inadequately elevated TSH (caused by thyrotropic cells in the pituitary gland insensitivity to TH). The cause of the disease is the mutation in TR-beta receptor gene. Depending on the clinical presentation generalised and pituitary resistance to TH are described. The syndrome is often misdiagnosed as hyperthyroidism and unnecessarily treated with anti-thyroid drugs. Some patients receive l-thyroxine treatment for apparent hypothyroidism. In this report, three patients are presented with a long history in our Clinic and Outpatient Clinic.