I'm a 31 inch waist and ordered a medium size. They fit perfectly BEFORE WASHING THEM. BOY DID THEY SHRINK. I should've ordered a size up. The waistband is too small for some reason. It's an unpleasant feel around your waist and on your balls. I literally had to go commando at work because they hurt so much: tight around my entire package. Great product but I'd order a size up: they WILL SHRINK after you wash them. P.S. If you're hung, i'd definitely order a size up!