Cotton fabric from men's boxers (underwear). When my late father-in-law died, I told my mother-in-law to send me some of his clothes and I would made a comfort quilt for her. I cried when I opened the box she sent me, because she had packed as if he was going on a short trip. 4 pair each of socks and boxers, 2 long-sleeved shirts, 2 short-sleeved shirts, 3 pairs of pants, and a jacket. I used everything except the socks and jacket. I don't know how the quilt has held up, it's only a few months old and I don't think it gets a lot of real heavy use.