Stretch fabric is basically a synthetic fabric that stretches to adapt to the contours of the body. Stretch fabric can be made from a variety of materials such as Lycra or spandex, but is most often manufactured from cotton blends. Stretch fabrics are also known as "power stretch" or "adhesive stretch" fabrics, as they rely on a chemical reaction between the stretch material and the human body's own natural collagen fibers to adhere to skin in a non-permanent manner. Stretch fabrics are either two-way stretch or four-way stretch.

In order to understand how stretch fabric works, it is important to have a basic understanding of the structure of spandex. Spandex is an industrial grade fabric, which has many advantages when it comes to manufacturing apparel. Spandex garments are strong and durable, and because they are able to stretch to fit the body, they do not become constrictive after being worn for an extended period of time. Spandex garments also are easy to maintain, as stretch marks do not form on these types of garments. While spandex has many practical uses, one of the main reasons that companies use this material is to create stretchable items such as shirts, pants, bibs, and baby diapers. Stretch fabric manufacturers are able to manipulate the properties of stretchable materials in a way that gives a clothing item the ability to stretch without becoming constrictive.

Stretch fabrics can be produced in a variety of forms, depending on the manufacturer's needs. They can be manufactured as either woven or knitted fabrics, and either man-made or natural fibers. A knitted piece of stretch fabric may retain its elasticity, while woven fabrics tend to retain more elasticity.

Two-way stretch fabric is one of the most commonly used types of stretch material, as it allows the user to stretch both directions simultaneously. This type of fabric also is most suitable for items that must withstand lots of movement. Examples of items that would make a good choice for this kind of stretch material are baby diapers, jumpers, and tights.

Two-way woven fabrics can also be made by machine, and they can offer even greater elasticity than those made by hand. Unlike two-way knit fabrics, this type of stretch fabric allows users to stretch both directions simultaneously. Some knitted fabrics can only stretch in one direction. Many manufacturers create two-way knit fabrics out of cross fiber or polyester, which allow users to stretch in both directions simultaneously. Some knitted products, such as baby blankets, do come with an option to stretch both ways.

Stretch fabrics are a convenient option for many different types of products. Being stretchy, they make for a great alternative to bulky, heavy fabrics. Many companies offer various types of spandex products, depending on the manufacturer's specific needs. In addition, there are some specialty spandex materials being developed that are geared toward certain applications.