A link has been noticed between thyroid disease and asthma; the mostfrequent reports have been of worsening of established asthma with the onset ofhyperthyroidism, with subsequent improvement of the asthma when the euthyroidstate is restored. The aim of this work was to determine whether systematic analysis of thyroidfunction is a useful requirement for all patients with difficult-to-manage asthma?The study was conducted in Chest Diseases Department of Kasr El Aini Hospital,Cairo University in the period from November 2006 to April 2007. All cases were subjected to history taking, full clinical examination both general and local of chest, cardiovascular system, central nervous system, abdominal, skin, skeletal, genital, ophthalmic systems. Hypertensive and Diabetic patients had been excluded, plain chest X-ray (postroanterior and lateral view), free T3, T4 and TSH were measured among 20 patients having acute severeasthma every 12 hours for 48 hours. Another sample was taken after controlling the attack.It was concluded that there is no increase or decrease in the thyroid hormones(T3, T4, and TSH) levels before and after the asthma attack.