PURPOSE: Breast augmentation with fat grafting has evolved from an obscure procedure to a groundswell of interest. For this procedure to have a role in plastic surgery, it must be performed in a reasonable period of time and yield predictable, reproducible results. The purpose of this study is three- fold: 1) to objectively examine the role of recipient site preparation using external pre-expansion, 2) to describe a standardized, time-efficient operative technique and 3) to validate recent reports this technique results in long term fat volume maintenance. METHODS: Over a two year period, 25 patients underwent breast enhancement with autologous fat grafting. Patients were screened for expansion compliance, result expectations, and breast risk factors. Patients were photographed and had intravenous contrast MRI, and/or three-dimensional breast imaging prior to 3 weeks of expansion. Liposuction with autologous fat grafting ranged from 220-650 cc per breast. High speed centrifugation was not used in this series. Low speed mega-volume syringe centrifugation was used to separate fat from crystalloid. Patients were followed postoperatively at regular intervals and had photographs, intravenous contrast quantitative MRI, and/or three-dimensional breast imaging at six months post procedure. RESULTS: All patients demonstrated visible volume increase to the breasts at six months. Quantitative MRI analysis revealed a mean volume increase of 250cc per breast. On a percent- increase basis, patient breast volumes increased from 60% to 180% of pre-expansion volume, for a mean increase of 1.2x original volume. Comparing pre-expansion volumes to 6 month postoperative volumes, the volumes were statistically different (P< .0000007). The variable that correlated best with final volume increase was the degree of preoperative expansion. The mean OR time was 2 hours. There were no infections, cysts, seromas, hematomas or tissue necrosis. DISCUSSION/CONCLUSION: External pre-expansion is an important variable in mega-volume fat grafting to the breasts. Patient selection and preoperative preparation are as mandatory as proper surgical technique in achieving a successful result. Mega volume fat grafting to the breast utilizing proper patient selection, a proven process of expansion, and efficient fat processing methods such as low speed mega volume syringe centrifugation combined with postoperative negative pressure result in a standardized, user-friendly technique. Breast augmentation with pre-expansion and autologous fat grafting can be performed in a time efficient manner with reproducible, long lasting results.