I made the mistake of buying a large the first pair I ordered. I like my pajamas loose and comfy, but these run very big. I still wear them, but only to bed. They're really soft cotton which ,surprisingly, doesn't shrink much even when washed in hot water. I bought three more pairs, one medium and two small. The small fit the best, although the medium is very comfortable. The price alone makes these a great buy, but I definitely recommend at least one size smaller than you normally wear.