BACKGROUND Fat necrosis is a common and potentially exasperating complication of autologous breast reconstruction. The authors performed a systematic review of the English literature on autologous breast reconstruction to determine significant patient and surgical factors that are predictors of postoperative fat necrosis. METHODS A PubMed search using the terms "fat necrosis" and "breast reconstruction" was conducted. Articles were screened using predetermined inclusion and exclusion criteria. Data collected included patient characteristics, reconstructive techniques used, and the specific postoperative morbidity of interest. Patient cohorts were pooled, and the incidence of fat necrosis was calculated in the presence and absence of each risk factor. Chi-square analysis was applied, and p < 0.05 was considered statistically significant. RESULTS Of 172 articles found, 70 met the inclusion criteria. The mean rate of fat necrosis was 11.3 percent. Deep inferior epigastric artery perforator flaps had the highest rate of fat necrosis (14.4 percent), followed by pedicled transverse rectus abdominis musculocutaneous (12.3 percent), superficial inferior epigastric artery (8.1 percent), and free transverse rectus abdominis musculocutaneous flaps (6.9 percent). Significant predictors of fat necrosis included obesity (p = 0.035), prereconstruction irradiation (p = 0.022), postreconstruction irradiation (p < 0.001), active smoking (p < 0.001), and abdominal scars (p = 0.05). Protective factors included supercharging (p < 0.001) and bilateral reconstruction (p = 0.01). CONCLUSIONS Although there is little agreement in the literature regarding risk factors for fat necrosis, the authors were able to demonstrate several significant predictors by systematically analyzing 70 articles. Improved knowledge of the risk factors for fat necrosis can help surgeons provide improved preoperative counseling and take measures to minimize the risk of this complication.