Background: Even though fat grafting has become widely used by plastic surgeons, most surgeons choose their method of fat grafting based almost entirely on anecdotal evidence. As more and more scientific studies appear in the literature, we now may have more objective, scientific evidence to support the use of specific techniques. Methods: The author critically reviewed all studies related to fat grafting research in the last 20 years in the English literature. To better summarize the findings of the studies, the fat grafting procedure was arbitrarily divided into 4 essential parts to determine the best donor sites and how the fat grafts should be harvested, processed, and placed. Results: While most studies show no difference in the viability of fat grafts harvested from different donor sites, one study shows that more adipose-derived stem cells (ADSCs) are found within the fat grafts harvested from the lower abdomen or inner thigh. Fat grafts harvested with syringe aspiration and processed with centrifugation at 1200 g for 3 min clearly have better viability. In addition, viable adipocytes and ADSCs as well as growth factors can be concentrated within the fat grafts after proper centrifugation. The studies also reinforce the principle that fat grafts, once placed, should have a maximal amount of contact with the vascularized tissue in the recipient site for better survival. Conclusions: Most scientific studies in fat grafting research support a more rationalized technique that should be selected by surgeons for fat grafting. The technique includes proper selection of donor sites, proper harvest and process of fat grafts, and proper placement of fat grafts. (C) 2011 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.