Rubber threads, known as Lastex and Lactron, have been known since 1925, but it is only since the late 1970s and early 1980s that synthetic plastic threads based on elastomeric long-chain polyester polyurethanes with some crosslinking have had a major impact on the market. Such fibers are known collectively in the U.S. as spandex fibers, defined as polymers containing at least 85% of polyurethane.

E. I. du Pont de Nemours & Company, Inc. produced the first spandex fiber in 1958. By 1959 there was sufficient demand that Du Pont decided to trademark the fiber, giving it the name Lycra. U.S. Rubber introduced an elastomeric fiber called Vyrene in the 1960s. During the 1960s there were on the market a number of other spandex fibers, including Cleerspun, Glospan, Numa, and Unel. Foreign manufacturers were also producing spandex under such tradenames as Roica, Fujibo, Kanebo, Mobilon, Opelon, and Espa, some of which found its way into the U.S. marketplace. By 1998, the U.S. spandex market was supplied by three manufacturers: Du Pont (Lycra), Globe Manufacturing Co. (Cleerspun, Glospan), and Bayer (Dorlastan).

Spandex is commonly used in such clothing articles as swimwear, foundation garments, brassieres, lingerie straps, sock tops, hosiery, and medical products requiring elasticity. Spandex is never used alone; it is always part of a blend of fibers, most frequently with nylon. It is more flexible than conventional elastic threads, and has two to three times the restraining power. It can be repeatedly stretched to over 500% without breaking and still recover instantly to its original length.