I ordered both a small and a medium because i have lost weight and seem to be in between sizes currently. lately i am anywhere from a 6 to a 10 in most retailer sizes. almost 5'4" and @140 lbs. i could have gotten away with the small. but my bust size is 36c/d. the small fit but didn't hang as well or feel as comfortable around the chest as the medium. i agree with a previous reviewer that this romper does have a tendency to hang awkwardly at the waist until and unless you pull the drawstring tigh