he main difference between cotton and polyester is that cotton is a natural fiber whereas polyester is a man-made fiber; it's synthetic. Polyester is a non-breathing fabric whereas cotton is breathing, it's a breathing fabric. Polyesters are a little more long lasting and durable whereas cotton will wear away after time. Polyester is basically indestructible. Cotton also feels a lot softer than polyester, depending on the fabric of course, because polyester comes in different forms like chiffon, poly-chiffon, stretchable fabrics like almost like a Lycra and cotton comes in a variation of blends as well. There is a combination of the two where it's cotton-poly. Nowadays, a lot of manufacturers use it to lower their prices where you get the advantages of cotton with the benefits of polyester. Also, another way to distinguish between cotton and polyester is polyester goes through a chemical treatment, whereas cotton doesn't go through as hard of a treatment as polyester. Cotton is easily dye-able and polyester doesn't dye as quickly. So, if you're sensitive or you tend to get allergic reactions, I would suggest staying away from a polyester especially for children's wear and just stick with cotton where it's a little more breathable. This is Patricia Samaniego and those were the differences between cotton and polyester.