100% cotton as the name applies is an all-natural-fiber fabric. 100% cotton fabric will shrink some when washed. I have read anywhere from 5-10% shrinkage of which most is from top to bottom. The better makers now use preshrunk material (see USEFUL TERMS) to keep the shrinkage factor down and cut the apparel bigger allowing for some shrinkage. 100% cotton fabric is made in many weights (5oz to 13oz depending on fabric) and tends to be knitted more loosely than 50/50 blended fabrics. 50/50 (50% cotton & 50% polyester) fabric that tends to be knitted more densely/closer thus presenting a tighter field for imprinting and, because of the polyester, hardly shrinks for most major brands. Fabric weights tend to be limited from 4.5oz to 6oz.