Heat (energy released) and cool (energy absorbed) are two types of PCMs that have been developed and adopted in clothing and textiles design. Many special function and smart textiles have adopted this concept such as: ski wear, diver dry suits, underwear, socks, hats, masks, gloves, shoes, firefighters' gear, bedding like sheets and pillowcases, and medical clothing. This paper discusses current PCM applications in clothing and explores future usage.