I ordered an XS, I am 5'2/115 lbs/34A. This body suit fit me fairly well. I say fairly well because my chest is small so it kind of looked like the straps were covering my boobs. I pulled up the straps and pinned them in place and it fit perfectly. The crotch is not a snap, it's a bra hook so if you feel like you need a bit more room buy some bra strap extenders and hook them in place.