In the recent decades, the microcapsules containing chemical materials with an ability to store the latent heat which results when a solid is changed into a liquid during melting or to the reverse transformation during cooling were studied; these materials are scientifically known as Phase Change Materials (PCMs). The chemical materials containing paraffin and alkyl hydrocarbons are very important in the manufacturing of microcapsules which used in specific applications for textile through their addition to materials for surface treatment or by their incorporation with the synthetic fibers during the processes of polymer transformation. Therefore, some thermal properties are provided to clothing components such as fibers and threads which in turn may control their thermal properties resulting in production of a new type of fabrics defined as Smart Clothing and Textiles which could positively interact with the general atmosphere and the surrounding environment to regulate the temperature providing protection and comfort to those who wear these fabrics regardless the temperature variations and changes in the surrounding environment, The objective of this study is to combine the specific properties of continuous yarns and short hairs in one thread using the core-spinning technique. So, the specific characteristics of each component of the final thread could be exploited in order to obtain innovative fabrics with distinctive thermal properties which designed for protection and comfort in high temperature environment. Three types of threads with different yarns were produced using a "Core-Spinning" technique wherein the thread axis is consisted from continuous and PCMs treated threads, while, the short fibers which cover the axis are composed of cotton and treated viscose and polyester. All fibers and treated threads were obtained from the company of Outlast Technologies®. The yarn samples were carried out at factory Spinning 3, Misr Spinning & Weaving Company, Mahalla El Kobra city, Gharbia, Egypt. The use of these threads was limited to the production of knitted fabrics which fit the underwear, the latter was chosen because of its close contact with human skin and therefore its effect on the micro climate; between the skin and cloth, will be significant and thus protect who dressed these clothes with comfortable feeling. Some of tests were carried out on the studied produced Jersey including thickness, water absorption ratio, air permeability, explosion resistance and Abrasion resistance. The obtained results showed that: Thickness: The N° 36 using polyester at the thread surface were the least thickness in produced fabrics, Water absorption ratio: the N° 24 using the viscose at the thread surface was the best water absorption ratio, Air permeability: The N° 36 using polyester at the thread surface was the highest air permeable, Explosion resistance: The N° 24 using polyester at the thread surface was the most resistant for explosion, Abrasion resistance: The N° 36 using polyester at the thread surface was the most resistant for Abrasion. Key words: microcapsules, Phase Change Materials (PCMs), Smart Textiles and Clothing, Core-Spinning