The aqueous alkaline reaction using sodium hydroxide on polyester fibers is a well-known process to give a silk-like fabric. In this process, hydrolytic scission of ester linkages of polyester chains occurs on the fiber surface. The key parameters of this process are NaOH concentration, temperature, treatment time, and pressure of squeezing rollers. The main goal of this study was to examine the thermal comfort features of polyester woven fabrics treated with an aqueous solution of caustic soda. It was found that the thermal comfort characteristics of alkaline treated polyester fabrics are significantly affected by the weight reduction parameters