When planning breast reduction surgery, a very common question from patients is their postoperative breast size. The purpose of this study was to determine whether we can accurately predict a patient's postoperative breast cup size following reduction mammoplasty. This study looks retrospectively at 100 patients who underwent a reduction mammoplasty to see if a consistent correlation exists between preoperative cup size, specimen weight, and postoperative cup size. 48 patients underwent a Free Nipple Reduction Mammoplasty while 52 patients had a reduction using the Inferior Pedicle Technique. In our series a size C breast cup size as obtained in 57% of the patients postoperatively, 23% size B, 24% size D, and 3% size DD. We found no consistent correlation between the amount resected and size achieved as many different specimen weights yielded similar cup sizes for each postoperative size. Thus, in our experience, postoperative cup size cannot accurately be predicted based on the amount resected from known preoperative cup size. We therefore can only tell our patients that in our series one half of the patients are a C cup size, one quarter are a B cup size and one quarter are a D cup size postoperatively.