These shirts are 100% cotton and even after quite a bit of washing (as in 1.5 years worth), I am happy to say that the colors are still like new, there has been NO PILLING and the fit is still excellent. The shirts feel soft and are a great weight - not a heavy, cheap cotton shirt, but not flimsy either. These are a fantastic item and I wish they would start making a women's version. Hear my plea, Amazon!
[Update: 1/29/20 - Amazon has expanded their Goodthreads line to women. Would love to see organic cotton and factory info about this line.]