I"m 6' and 167lbs. I wear a 33 waist and a 40R jacket. I usually wear medium in shirts like Ralph Lauren, Bannana Republic, etc. but a medium in J&M shirts are too short in the arms and shoulders for me. I have to go to a large but then the trunc is too baggy. I purchased a large and I'm keeping it but wished it fit better. Looks big on me. They need a slim large or make medium like other shirts.