Im a 36D and ordered, I believe, the XL.  It is currently unavailable and is no tag in the item itself so I cannot exactly remember..  it fits well on one of the middle hooks which is what I want.  Overall I am happy with it.  The cups fit decantly and the clevage isn't overkill...  I was worried being a D cup since a lot of reviews for this type of item say the cups don't get bigger with the sizes..  They are fine, could be a tad bigger but no biggie.  Two things I don't like are, one there isn't much under bust support..  its kinda baggy there..  and two, there is non-slip stuff around the inside, which is great except makes it VERY difficult to put on by yourself because you have to hook it in the front and then slide it around... the non-slip stuff making that hard.  If you have someone to hook you in the back then you're good.