I'm 5'1 at 110lbs with a full 34c cup and waist 28 1/2. At the time of purchase my waist was 30 and I ordered the Medium. When I got the dress, my waste was 29. The dress was obviously too big. It just drooped on me. It's also longer than I expected on me. BUT... this dress is made VERY well. Thick and stretchy. I still love the dress and it's nothing a little alteration can't fix. All I have to do is sew in the sides and bring the length up. So no concerns there. I DO wish I ordered the small.. then I wouldn't have to do this work. I hate returning stuff.