Ive got a 33 waiste and went with a medium. The fabric is incredibly soft, which I love, but the down sides outweigh the good, unfortunately. Immediately, I loved the pouch aspect but they ride up instantly and the back side will also ride up, giving you a slight wedgie all day long. Very annoying. I contacted the company and they promptly sent out a large which solved the wedgie problem but continued to ride up my thighs right away. I really hoped these would work out for me but the search continues.