These sheets are 100% polyester, yet they're still soft to the touch and you should sleep comfortably as a result! However since they're polyester they won't keep cool as well as other cotton sheets. Also these sheets are moreso intended for thicker mattresses (think maybe pillowtop) They will definitely fit my plush mattress, but the fitted sheet is a little on the "baggy" side. Not a problem though and I'm not docking any stars for it. Still a great buy!