I am 4'10" and normally wear a size small.  I purchased this in a medium because I was afraid it would be extremely tight.  It was still tight in a medium (fight to get over your chest- tight).  Also it was extremely short.  I had a hard time keeping one side of this dress over my bottom. (One side is longer than the other).  I know that this dress is supposed to be short and tight- it's a sexy costume.  But it was uncomfortably tight and way too short (I was either pulling the front up- or the back down all night).  If you are taller or bigger than I am, I would suggest another dress or ordering a larger size. Also, the material is a very thin, "nylon"-type material.  All in all, I enjoyed myself at the party and the dress worked for what I needed.  I would never wear it again, though.