I admit that I didn't look to see if the fabric was all cotton before I bought these sheets. My mistake. I was seduced by the "1800 thread count" and made the rash assumption that it was all cotton. The sheets are some kind of "micro fiber." They are cheaply made, and the fiber catches on my cotton pajamas. They are hot and do not breathe. Plus the colors are not as represented; they are ugly as sin. I made the mistake of washing them before using, so I cannot return them. I will be donating them, although not in good conscience, because i don't think anyone will enjoy these.